新增市場情報候選佇列 writer preflight

TODO_NEXT_STEPS.txt

@@ -117,6 +117,7 @@
    - V10.228 補 PPT 視覺 QA 背景狀態卡：新增 `/observability/ppt_audit/vision_status` 與頁面 Vision QA 狀態卡，讓立即視覺 QA 排入後可看 queued/running/completed/error 與最近審核摘要，不必刷新猜測。
    - V10.229 修正 PPT 視覺 QA 多 worker 狀態漂移：將 queued/running/completed/error 寫入 `/app/data/ppt_vision_audit_status.json` runtime state，所有 Gunicorn worker 共用同一份狀態並阻擋重複排入。
    - Phase 55 candidate queue writer CLI gate：新增 `/api/market_intel/manual_sample_review/candidate_queue_writer_status` POST、`scripts/market_intel_candidate_queue_writer.py` 與 UI writer gate 按鈕，定義 `MARKET_INTEL_QUEUE_WRITE_APPROVAL` 一次性 token、execute/apply flags、備份、migration smoke 與 rollback gate；本階段仍不開 DB connection、不寫 `market_alert_review_queue`、不 commit、不掛 scheduler；版本同步至 V10.230。
+   - Phase 56 candidate queue writer preflight：新增 `/api/market_intel/manual_sample_review/candidate_queue_writer_preflight` POST 與 `services/market_intel/candidate_queue_writer_preflight.py`，檢查 transaction payload key 到 `market_alert_review_queue` 欄位映射、缺欄與 dedupe unique index；頁面預設 execute=false 不連 DB，CLI 可明確 `--read-only-preflight` 只讀 catalog；版本同步至 V10.232。
    - Schema smoke：`tests/test_market_intel_skeleton.py` 檢查 `Base.metadata` 內含 ADR-035 八張 `market_*` tables。
    - Desktop UI QA：本機只註冊 `market_intel_bp` 的 Flask harness 載入 `/market_intel`，確認 Phase 15、候選預覽、writer preview、安全 flags、點陣暖紙視覺正常，console error 0。
    - API QA：`/api/market_intel/schema_smoke` 通過 7 張表與 `market_platforms` 必要欄位檢查；`/api/market_intel/platform_seed_writer_plan` 回傳 4 筆 dry-run upsert preview，`writes_executed=false`，四平台皆 `blocked_dry_run_only`。

config.py

@@ -320,7 +320,7 @@ YOUTUBE_API_KEY = os.getenv('YOUTUBE_API_KEY', '')
 # ==========================================
 # 系統版本與路徑
 # ==========================================
-SYSTEM_VERSION = "V10.231"
+SYSTEM_VERSION = "V10.232"
 LOG_FILE_PATH = os.path.join(BASE_DIR, 'logs/system.log')
 public_url = PUBLIC_URL  # 用於模板顯示
 

docs/adr/ADR-035-cross-platform-market-campaign-intelligence.md

@@ -181,6 +181,7 @@ EwoooC 目前已有 MOMO EDM / 節慶活動資料、`promo_products`、PChome
 - 2026-05-19 追加 manual sample candidate queue approval：`/api/market_intel/manual_sample_review/candidate_queue_approval` 將 queue draft 對齊既有 `market_alert_review_queue` 契約，輸出 row preview、必填欄位 gate、寫入 flags、備份與人工批准 gate。此入口保持 CSRF 保護，不建立 approval record、不寫 review queue、不開 DB transaction、不掛 scheduler。
 - 2026-05-19 追加 manual sample candidate queue transaction：`/api/market_intel/manual_sample_review/candidate_queue_transaction` 將 queue row preview 轉成 idempotent insert statement preview、payload hash、runtime order 與 rollback plan。此入口保持 CSRF 保護，不開 DB connection、不開 transaction、不 commit、不建立 approval record、不寫 `market_alert_review_queue`。
 - 2026-05-19 追加 candidate queue writer CLI gate：`services.market_intel.candidate_queue_writer_cli`、`scripts/market_intel_candidate_queue_writer.py` 與 `/api/market_intel/manual_sample_review/candidate_queue_writer_status` 定義 `MARKET_INTEL_QUEUE_WRITE_APPROVAL` 一次性 token、execute/apply flags、備份、migration smoke 與 rollback gate。此階段只回 writer status，不開 DB connection、不啟用實際 writer、不寫 `market_alert_review_queue`、不掛 scheduler。
+- 2026-05-19 追加 candidate queue writer preflight：`services.market_intel.candidate_queue_writer_preflight` 與 `/api/market_intel/manual_sample_review/candidate_queue_writer_preflight` 檢查 transaction preview payload key 到 `market_alert_review_queue` 欄位映射、缺欄與 dedupe unique index。UI 預設 `execute=false` 不連 DB；CLI 明確 `--read-only-preflight` 時也只查 catalog，不寫 DB、不 commit、不掛 scheduler。
 
 ### Phase 4：Coupang / Shopee Adapter
 

routes/README.md

@@ -19,7 +19,7 @@
 | `edm_routes.py` | EDM 與節慶儀表板 | `/edm`, `/festival` |
 | `monthly_routes.py` | 月結分析 | `/monthly_summary_analysis`, `/api/monthly_summary_data` |
 | `daily_sales_routes.py` | 當日業績 | `/daily_sales`, `/daily_sales/export*` |
-| `market_intel_routes.py` | 市場情報 Phase 55 candidate queue writer CLI gate | `/market_intel`, `/market_intel/*`, `/api/market_intel/status`, `/api/market_intel/schema`, `/api/market_intel/schema_smoke`, `/api/market_intel/schema_db_probe`, `/api/market_intel/platform_seed_db_diff`, `/api/market_intel/legacy_source_bridge`, `/api/market_intel/mcp_readiness`, `/api/market_intel/mcp_tool_contract`, `/api/market_intel/mcp_deploy_preflight`, `/api/market_intel/mcp_activation_runbook`, `/api/market_intel/mcp_fetch_gate`, `/api/market_intel/scheduler_plan`, `/api/market_intel/manual_sample_plan`, `/api/market_intel/manual_sample_acceptance`, `/api/market_intel/manual_sample_review`, `/api/market_intel/manual_sample_review/evaluate`, `/api/market_intel/manual_sample_review/candidate_handoff`, `/api/market_intel/manual_sample_review/candidate_queue_draft`, `/api/market_intel/manual_sample_review/candidate_queue_approval`, `/api/market_intel/manual_sample_review/candidate_queue_transaction`, `/api/market_intel/manual_sample_review/candidate_queue_writer_status`, `/api/market_intel/match_review_plan`, `/api/market_intel/opportunity_plan`, `/api/market_intel/opportunity_scoring_plan`, `/api/market_intel/opportunity_evidence_plan`, `/api/market_intel/opportunity_alert_plan`, `/api/market_intel/adapters`, `/api/market_intel/dry_run_plan`, `/api/market_intel/discovery_plan`, `/api/market_intel/manual_discovery`, `/api/market_intel/candidate_preview`, `/api/market_intel/platform_seed_plan`, `/api/market_intel/platform_seed_write_guard`, `/api/market_intel/platform_seed_writer_plan`, `/api/market_intel/migration_blueprint`, `/api/market_intel/migration_apply_drill`, `/api/market_intel/migration_catalog_review`, `/api/market_intel/migration_live_smoke`, `/api/market_intel/live_db_inventory`, `/api/market_intel/seed_writer_cli_status`, `/api/market_intel/write_approval_runbook`, `/api/market_intel/deployment_readiness` |
+| `market_intel_routes.py` | 市場情報 Phase 56 candidate queue writer preflight | `/market_intel`, `/market_intel/*`, `/api/market_intel/status`, `/api/market_intel/schema`, `/api/market_intel/schema_smoke`, `/api/market_intel/schema_db_probe`, `/api/market_intel/platform_seed_db_diff`, `/api/market_intel/legacy_source_bridge`, `/api/market_intel/mcp_readiness`, `/api/market_intel/mcp_tool_contract`, `/api/market_intel/mcp_deploy_preflight`, `/api/market_intel/mcp_activation_runbook`, `/api/market_intel/mcp_fetch_gate`, `/api/market_intel/scheduler_plan`, `/api/market_intel/manual_sample_plan`, `/api/market_intel/manual_sample_acceptance`, `/api/market_intel/manual_sample_review`, `/api/market_intel/manual_sample_review/evaluate`, `/api/market_intel/manual_sample_review/candidate_handoff`, `/api/market_intel/manual_sample_review/candidate_queue_draft`, `/api/market_intel/manual_sample_review/candidate_queue_approval`, `/api/market_intel/manual_sample_review/candidate_queue_transaction`, `/api/market_intel/manual_sample_review/candidate_queue_writer_status`, `/api/market_intel/manual_sample_review/candidate_queue_writer_preflight`, `/api/market_intel/match_review_plan`, `/api/market_intel/opportunity_plan`, `/api/market_intel/opportunity_scoring_plan`, `/api/market_intel/opportunity_evidence_plan`, `/api/market_intel/opportunity_alert_plan`, `/api/market_intel/adapters`, `/api/market_intel/dry_run_plan`, `/api/market_intel/discovery_plan`, `/api/market_intel/manual_discovery`, `/api/market_intel/candidate_preview`, `/api/market_intel/platform_seed_plan`, `/api/market_intel/platform_seed_write_guard`, `/api/market_intel/platform_seed_writer_plan`, `/api/market_intel/migration_blueprint`, `/api/market_intel/migration_apply_drill`, `/api/market_intel/migration_catalog_review`, `/api/market_intel/migration_live_smoke`, `/api/market_intel/live_db_inventory`, `/api/market_intel/seed_writer_cli_status`, `/api/market_intel/write_approval_runbook`, `/api/market_intel/deployment_readiness` |
 | `api_routes.py` | 通用任務與查詢 API | `/api/run_task`, `/api/history/*` |
 | `export_routes.py` | 匯出功能 | `/api/export/*` |
 | `import_routes.py` | 匯入功能 | `/api/import_excel`, `/api/import/monthly_summary` |

routes/market_intel_routes.py

@@ -12,6 +12,9 @@ from services.market_intel import MarketIntelService
 from services.market_intel.candidate_queue_writer_cli import (
     build_candidate_queue_writer_cli_plan,
 )
+from services.market_intel.candidate_queue_writer_preflight import (
+    build_candidate_queue_writer_preflight,
+)
 
 
 TAIPEI_TZ = timezone(timedelta(hours=8))
@@ -318,8 +321,13 @@ def market_intel_manual_sample_candidate_queue_writer_status():
         payload_error=payload_error,
         limit=limit,
     )
+    writer_preflight = build_candidate_queue_writer_preflight(
+        transaction_preview=transaction_preview,
+        execute_requested=False,
+    )
     data = build_candidate_queue_writer_cli_plan(
         transaction_preview=transaction_preview,
+        writer_preflight=writer_preflight,
         execute_requested=execute_requested,
         apply_real_write=apply_real_write,
         approval_token=None,
@@ -330,6 +338,37 @@ def market_intel_manual_sample_candidate_queue_writer_status():
     return jsonify(data), status_code
 
 
+@market_intel_bp.route(
+    "/api/market_intel/manual_sample_review/candidate_queue_writer_preflight",
+    methods=["POST"],
+)
+@login_required
+def market_intel_manual_sample_candidate_queue_writer_preflight():
+    payload = request.get_json(silent=True)
+    limit = request.args.get("limit", default=20, type=int)
+    execute_requested = request.args.get("execute", "false").lower() == "true"
+    service = _service()
+    payload_error = None
+    if not isinstance(payload, dict):
+        sample_result = None
+        payload_error = "invalid_json_object"
+    else:
+        sample_result = payload.get("sample_result", payload)
+
+    transaction_preview = service.build_manual_sample_candidate_queue_transaction(
+        sample_result=sample_result,
+        payload_error=payload_error,
+        limit=limit,
+    )
+    data = build_candidate_queue_writer_preflight(
+        transaction_preview=transaction_preview,
+        execute_requested=execute_requested,
+    )
+    data["phase"] = service.phase
+    status_code = 400 if payload_error else 200
+    return jsonify(data), status_code
+
+
 @market_intel_bp.route("/api/market_intel/match_review_plan")
 @login_required
 def market_intel_match_review_plan():

scripts/market_intel_candidate_queue_writer.py

@@ -24,6 +24,9 @@ with contextlib.redirect_stdout(sys.stderr):
         APPROVAL_ENV_VAR,
         build_candidate_queue_writer_cli_plan,
     )
+    from services.market_intel.candidate_queue_writer_preflight import (  # noqa: E402
+        build_candidate_queue_writer_preflight,
+    )
 
 
 def parse_args(argv=None):
@@ -50,6 +53,11 @@ def parse_args(argv=None):
         default=None,
         help=f"One-time approval token checked against {APPROVAL_ENV_VAR}.",
     )
+    parser.add_argument(
+        "--read-only-preflight",
+        action="store_true",
+        help="Run read-only schema / payload preflight before returning the gate.",
+    )
     return parser.parse_args(argv)
 
 
@@ -75,8 +83,13 @@ def main(argv=None):
         sample_result=sample_result,
         payload_error=payload_error,
     )
+    writer_preflight = build_candidate_queue_writer_preflight(
+        transaction_preview=transaction_preview,
+        execute_requested=args.read_only_preflight,
+    )
     plan = build_candidate_queue_writer_cli_plan(
         transaction_preview=transaction_preview,
+        writer_preflight=writer_preflight,
         execute_requested=args.execute,
         apply_real_write=args.apply_real_write,
         approval_token=args.approval_token,

services/market_intel/candidate_queue_writer_cli.py

@@ -23,6 +23,7 @@ def _approval_token_valid(approval_token, approval_token_secret):
 def build_candidate_queue_writer_cli_plan(
     *,
     transaction_preview,
+    writer_preflight=None,
     execute_requested=False,
     approval_token=None,
     approval_token_secret=None,
@@ -38,6 +39,9 @@ def build_candidate_queue_writer_cli_plan(
     transaction_preview_created = bool(
         transaction_preview.get("transaction_preview_created")
     )
+    preflight_ready = bool(
+        writer_preflight and writer_preflight.get("ready_for_writer_review")
+    )
     writer_enabled = False
     gates = [
         {
@@ -80,6 +84,11 @@ def build_candidate_queue_writer_cli_plan(
             "label": "--apply-real-write flag was explicitly provided",
             "passed": bool(apply_real_write),
         },
+        {
+            "key": "queue_writer_preflight_ready",
+            "label": "候選 queue writer schema / payload preflight 已通過",
+            "passed": preflight_ready,
+        },
         {
             "key": "backup_verified",
             "label": "正式寫入前必須確認最新備份已完成",
@@ -146,6 +155,14 @@ def build_candidate_queue_writer_cli_plan(
             "conflict_policy": summary.get("conflict_policy"),
         },
         "transaction_preview": transaction_preview,
+        "writer_preflight": writer_preflight or {
+            "mode": "candidate_queue_writer_preflight_not_requested",
+            "ready_for_writer_review": False,
+            "read_only_query_executed": False,
+            "database_connection_opened": False,
+            "database_write_executed": False,
+            "database_commit_executed": False,
+        },
         "rollback_plan": [
             {
                 "key": "no_write_no_db_rollback_required",

services/market_intel/candidate_queue_writer_preflight.py

@@ -0,0 +1,308 @@
+"""市場情報候選 queue writer 只讀 preflight。
+
+本模組檢查 transaction preview payload 能否對齊正式
+`market_alert_review_queue` 欄位與 dedupe unique index；預設不連 DB，
+execute=true 時也只查 catalog，不寫入、不 commit、不掛 scheduler。
+"""
+
+from sqlalchemy import create_engine, text
+
+
+QUEUE_TABLE = "market_alert_review_queue"
+PAYLOAD_COLUMN_MAP = {
+    "alert_candidate_id": "alert_candidate_id",
+    "review_state": "review_state",
+    "priority_lane": "priority_lane",
+    "threshold_level": "threshold_level",
+    "total_score": "total_score",
+    "evidence_bundle_id": "evidence_bundle_id",
+    "dedupe_key": "dedupe_key",
+    "source_batch_id": "source_batch_id",
+    "metadata_json_preview": "metadata_json",
+}
+
+
+def _statement_payload_keys(transaction_preview):
+    keys = set()
+    for statement in transaction_preview.get("statements", []):
+        keys.update(statement.get("parameter_keys", []))
+    return sorted(keys)
+
+
+def _mapped_columns(payload_keys):
+    mapped = {}
+    unmapped = []
+    for key in payload_keys:
+        column = PAYLOAD_COLUMN_MAP.get(key)
+        if column:
+            mapped[key] = column
+        else:
+            unmapped.append(key)
+    return mapped, unmapped
+
+
+def _planned_result(transaction_preview, payload_keys, mapped, unmapped):
+    mapped_columns = sorted(set(mapped.values()))
+    return {
+        "mode": "candidate_queue_writer_preflight_planned",
+        "target_table": QUEUE_TABLE,
+        "execute_requested": False,
+        "read_only_query_executed": False,
+        "database_connection_opened": False,
+        "database_session_created": False,
+        "explicit_transaction_opened": False,
+        "database_write_executed": False,
+        "database_commit_executed": False,
+        "database_rollback_executed": False,
+        "external_network_executed": False,
+        "scheduler_attached": False,
+        "table_exists": False,
+        "schema_ready": False,
+        "ready_for_writer_review": False,
+        "ready_for_real_write": False,
+        "transaction_preview_created": bool(
+            transaction_preview.get("transaction_preview_created")
+        ),
+        "statement_count": len(transaction_preview.get("statements", [])),
+        "payload_keys": payload_keys,
+        "payload_column_map": mapped,
+        "mapped_insert_columns": mapped_columns,
+        "unmapped_payload_keys": unmapped,
+        "existing_columns": [],
+        "missing_insert_columns": mapped_columns,
+        "dedupe_unique_index_present": False,
+        "index_names": [],
+        "blocked_reasons": [
+            "execute_false_planned_only",
+            "queue_writer_preflight_not_loaded",
+            "candidate_queue_writer_execution_not_enabled",
+        ],
+        "safety_contract": _safety_contract(),
+    }
+
+
+def _probe_postgresql(conn):
+    columns = conn.execute(
+        text(
+            """
+            SELECT column_name, data_type, is_nullable
+            FROM information_schema.columns
+            WHERE table_schema = ANY (current_schemas(false))
+              AND table_name = :table_name
+            ORDER BY ordinal_position
+            """
+        ),
+        {"table_name": QUEUE_TABLE},
+    ).fetchall()
+    indexes = conn.execute(
+        text(
+            """
+            SELECT indexname, indexdef
+            FROM pg_indexes
+            WHERE schemaname = ANY (current_schemas(false))
+              AND tablename = :table_name
+            ORDER BY indexname
+            """
+        ),
+        {"table_name": QUEUE_TABLE},
+    ).fetchall()
+    return [
+        {
+            "name": row._mapping["column_name"],
+            "type": row._mapping["data_type"],
+            "nullable": row._mapping["is_nullable"] == "YES",
+        }
+        for row in columns
+    ], [
+        {
+            "name": row._mapping["indexname"],
+            "definition": row._mapping["indexdef"],
+            "unique": "UNIQUE" in str(row._mapping["indexdef"]).upper(),
+        }
+        for row in indexes
+    ]
+
+
+def _probe_sqlite(conn):
+    columns = conn.execute(text(f"PRAGMA table_info({QUEUE_TABLE})")).fetchall()
+    indexes = conn.execute(text(f"PRAGMA index_list({QUEUE_TABLE})")).fetchall()
+    column_rows = [
+        {
+            "name": row._mapping["name"],
+            "type": row._mapping["type"],
+            "nullable": not bool(row._mapping["notnull"]),
+        }
+        for row in columns
+    ]
+    index_rows = []
+    for row in indexes:
+        index_name = row._mapping["name"]
+        indexed_columns = conn.execute(text(f"PRAGMA index_info({index_name})")).fetchall()
+        index_rows.append(
+            {
+                "name": index_name,
+                "definition": ",".join(item._mapping["name"] for item in indexed_columns),
+                "unique": bool(row._mapping["unique"]),
+            }
+        )
+    return column_rows, index_rows
+
+
+def _dedupe_unique_index_present(index_rows):
+    for row in index_rows:
+        definition = str(row.get("definition") or "")
+        if row.get("unique") and "dedupe_key" in definition:
+            return True
+    return False
+
+
+def _safety_contract():
+    return {
+        "read_only_catalog_query_only": True,
+        "does_not_open_transaction": True,
+        "does_not_commit": True,
+        "does_not_insert_queue_rows": True,
+        "does_not_attach_scheduler": True,
+        "target_table": QUEUE_TABLE,
+    }
+
+
+def build_candidate_queue_writer_preflight(
+    *,
+    transaction_preview,
+    execute_requested=False,
+    database_url=None,
+    database_type=None,
+    engine=None,
+):
+    """建立候選 queue writer preflight；execute=true 仍只做 catalog read。"""
+    payload_keys = _statement_payload_keys(transaction_preview)
+    mapped, unmapped = _mapped_columns(payload_keys)
+    if not execute_requested:
+        return _planned_result(transaction_preview, payload_keys, mapped, unmapped)
+
+    from config import DATABASE_PATH, DATABASE_TYPE
+
+    effective_database_type = (database_type or DATABASE_TYPE or "").lower()
+    effective_database_url = database_url or DATABASE_PATH
+    created_engine = False
+    connection_opened = False
+
+    try:
+        if engine is None:
+            connect_args = {}
+            if effective_database_type == "postgresql":
+                connect_args = {
+                    "connect_timeout": 8,
+                    "options": "-c statement_timeout=15000",
+                }
+            engine = create_engine(
+                effective_database_url,
+                isolation_level="AUTOCOMMIT",
+                pool_pre_ping=True,
+                connect_args=connect_args,
+            )
+            created_engine = True
+
+        with engine.connect() as conn:
+            connection_opened = True
+            if effective_database_type == "postgresql":
+                column_rows, index_rows = _probe_postgresql(conn)
+            else:
+                column_rows, index_rows = _probe_sqlite(conn)
+
+        existing_columns = sorted(row["name"] for row in column_rows)
+        mapped_columns = sorted(set(mapped.values()))
+        missing_columns = [
+            column for column in mapped_columns
+            if column not in set(existing_columns)
+        ]
+        table_exists = bool(column_rows)
+        dedupe_unique = _dedupe_unique_index_present(index_rows)
+        schema_ready = bool(table_exists and not missing_columns and dedupe_unique)
+        payload_mappable = bool(payload_keys and not unmapped)
+        ready_for_writer_review = bool(schema_ready and payload_mappable)
+        blocked_reasons = ["candidate_queue_writer_execution_not_enabled"]
+        if not table_exists:
+            blocked_reasons.insert(0, "queue_table_missing")
+        if missing_columns:
+            blocked_reasons.insert(0, "queue_insert_columns_missing")
+        if unmapped:
+            blocked_reasons.insert(0, "queue_payload_keys_unmapped")
+        if not dedupe_unique:
+            blocked_reasons.insert(0, "dedupe_unique_index_missing")
+        if not payload_keys:
+            blocked_reasons.insert(0, "transaction_statement_payload_missing")
+
+        return {
+            "mode": "candidate_queue_writer_preflight_read_only",
+            "target_table": QUEUE_TABLE,
+            "execute_requested": True,
+            "read_only_query_executed": True,
+            "database_connection_opened": connection_opened,
+            "database_session_created": False,
+            "explicit_transaction_opened": False,
+            "database_write_executed": False,
+            "database_commit_executed": False,
+            "database_rollback_executed": False,
+            "external_network_executed": False,
+            "scheduler_attached": False,
+            "table_exists": table_exists,
+            "schema_ready": schema_ready,
+            "ready_for_writer_review": ready_for_writer_review,
+            "ready_for_real_write": False,
+            "transaction_preview_created": bool(
+                transaction_preview.get("transaction_preview_created")
+            ),
+            "statement_count": len(transaction_preview.get("statements", [])),
+            "payload_keys": payload_keys,
+            "payload_column_map": mapped,
+            "mapped_insert_columns": mapped_columns,
+            "unmapped_payload_keys": unmapped,
+            "existing_columns": existing_columns,
+            "missing_insert_columns": missing_columns,
+            "dedupe_unique_index_present": dedupe_unique,
+            "index_names": [row["name"] for row in index_rows],
+            "blocked_reasons": blocked_reasons,
+            "safety_contract": _safety_contract(),
+        }
+    except Exception as exc:
+        return {
+            "mode": "candidate_queue_writer_preflight_error",
+            "target_table": QUEUE_TABLE,
+            "execute_requested": True,
+            "read_only_query_executed": False,
+            "database_connection_opened": connection_opened,
+            "database_session_created": False,
+            "explicit_transaction_opened": False,
+            "database_write_executed": False,
+            "database_commit_executed": False,
+            "database_rollback_executed": False,
+            "external_network_executed": False,
+            "scheduler_attached": False,
+            "table_exists": False,
+            "schema_ready": False,
+            "ready_for_writer_review": False,
+            "ready_for_real_write": False,
+            "transaction_preview_created": bool(
+                transaction_preview.get("transaction_preview_created")
+            ),
+            "statement_count": len(transaction_preview.get("statements", [])),
+            "payload_keys": payload_keys,
+            "payload_column_map": mapped,
+            "mapped_insert_columns": sorted(set(mapped.values())),
+            "unmapped_payload_keys": unmapped,
+            "existing_columns": [],
+            "missing_insert_columns": sorted(set(mapped.values())),
+            "dedupe_unique_index_present": False,
+            "index_names": [],
+            "blocked_reasons": [
+                "queue_writer_preflight_error",
+                "candidate_queue_writer_execution_not_enabled",
+            ],
+            "error_message": str(exc),
+            "safety_contract": _safety_contract(),
+        }
+    finally:
+        if created_engine:
+            engine.dispose()

services/market_intel/deployment_readiness.py

@@ -6,6 +6,9 @@
 from services.market_intel.candidate_queue_writer_cli import (
     build_candidate_queue_writer_cli_plan,
 )
+from services.market_intel.candidate_queue_writer_preflight import (
+    build_candidate_queue_writer_preflight,
+)
 
 
 def build_deployment_readiness_preview(
@@ -40,8 +43,13 @@ def build_deployment_readiness_preview(
     manual_sample_candidate_queue_transaction = (
         service.build_manual_sample_candidate_queue_transaction(sample_result={})
     )
+    candidate_queue_writer_preflight = build_candidate_queue_writer_preflight(
+        transaction_preview=manual_sample_candidate_queue_transaction,
+        execute_requested=False,
+    )
     candidate_queue_writer_cli_status = build_candidate_queue_writer_cli_plan(
         transaction_preview=manual_sample_candidate_queue_transaction,
+        writer_preflight=candidate_queue_writer_preflight,
     )
     match_review_plan = service.build_match_review_plan()
     opportunity_plan = service.build_opportunity_plan()
@@ -210,6 +218,15 @@ def build_deployment_readiness_preview(
             and not candidate_queue_writer_cli_status["database_commit_executed"]
             and not candidate_queue_writer_cli_status["scheduler_attached"]
         ),
+        "candidate_queue_writer_preflight_planned_safe": bool(
+            candidate_queue_writer_preflight["mode"]
+            == "candidate_queue_writer_preflight_planned"
+            and not candidate_queue_writer_preflight["read_only_query_executed"]
+            and not candidate_queue_writer_preflight["database_connection_opened"]
+            and not candidate_queue_writer_preflight["database_write_executed"]
+            and not candidate_queue_writer_preflight["database_commit_executed"]
+            and not candidate_queue_writer_preflight["scheduler_attached"]
+        ),
         "match_review_plan_preview_safe": bool(
             match_review_plan["mode"] == "match_review_plan_preview"
             and not match_review_plan["review_queue_created"]
@@ -460,6 +477,7 @@ def build_deployment_readiness_preview(
         "manual_sample_candidate_queue_transaction": (
             manual_sample_candidate_queue_transaction
         ),
+        "candidate_queue_writer_preflight": candidate_queue_writer_preflight,
         "candidate_queue_writer_cli_status": candidate_queue_writer_cli_status,
         "match_review_plan": match_review_plan,
         "opportunity_plan": opportunity_plan,

services/market_intel/service.py

@@ -108,7 +108,7 @@ class MarketIntelRuntimeStatus:
 class MarketIntelService:
     """市場情報入口服務，先集中 feature gate 與安全狀態。"""
 
-    phase = "phase_55_candidate_queue_writer_cli_gate"
+    phase = "phase_56_candidate_queue_writer_preflight"
 
     def get_runtime_status(self) -> MarketIntelRuntimeStatus:
         return MarketIntelRuntimeStatus(

templates/market_intel/disabled.html

@@ -251,7 +251,7 @@
         align-items: stretch;
         display: grid;
         gap: 0.75rem;
-        grid-template-columns: minmax(0, 1fr) auto auto auto auto auto auto;
+        grid-template-columns: minmax(0, 1fr) auto auto auto auto auto auto auto;
         min-width: 0;
     }
 
@@ -591,6 +591,9 @@
             <button class="market-intel-icon-button" type="button" title="檢查 queue writer CLI gate" data-market-intel-sample-candidate-queue-writer>
                 <i class="fas fa-terminal" aria-hidden="true"></i>
             </button>
+            <button class="market-intel-icon-button" type="button" title="檢查 queue writer preflight" data-market-intel-sample-candidate-queue-preflight>
+                <i class="fas fa-database" aria-hidden="true"></i>
+            </button>
         </div>
     </div>
 
@@ -920,6 +923,7 @@
         const sampleCandidateQueueApproval = sampleReviewRoot ? sampleReviewRoot.querySelector('[data-market-intel-sample-candidate-queue-approval]') : null;
         const sampleCandidateQueueTransaction = sampleReviewRoot ? sampleReviewRoot.querySelector('[data-market-intel-sample-candidate-queue-transaction]') : null;
         const sampleCandidateQueueWriter = sampleReviewRoot ? sampleReviewRoot.querySelector('[data-market-intel-sample-candidate-queue-writer]') : null;
+        const sampleCandidateQueuePreflight = sampleReviewRoot ? sampleReviewRoot.querySelector('[data-market-intel-sample-candidate-queue-preflight]') : null;
         const sampleReviewEndpoint = "{{ url_for('market_intel.market_intel_manual_sample_review') }}";
         const sampleReviewEvaluateEndpoint = "{{ url_for('market_intel.market_intel_manual_sample_review_evaluate') }}";
         const sampleCandidateHandoffEndpoint = "{{ url_for('market_intel.market_intel_manual_sample_candidate_handoff') }}";
@@ -927,6 +931,7 @@
         const sampleCandidateQueueApprovalEndpoint = "{{ url_for('market_intel.market_intel_manual_sample_candidate_queue_approval') }}";
         const sampleCandidateQueueTransactionEndpoint = "{{ url_for('market_intel.market_intel_manual_sample_candidate_queue_transaction') }}";
         const sampleCandidateQueueWriterEndpoint = "{{ url_for('market_intel.market_intel_manual_sample_candidate_queue_writer_status') }}";
+        const sampleCandidateQueuePreflightEndpoint = "{{ url_for('market_intel.market_intel_manual_sample_candidate_queue_writer_preflight') }}";
         const schedulerMeta = schedulerRoot ? schedulerRoot.querySelector('[data-market-intel-scheduler-meta]') : null;
         const schedulerBody = schedulerRoot ? schedulerRoot.querySelector('[data-market-intel-scheduler-body]') : null;
         const schedulerRefresh = schedulerRoot ? schedulerRoot.querySelector('[data-market-intel-scheduler-refresh]') : null;
@@ -2323,6 +2328,67 @@
             }
         };
 
+        const renderCandidateQueuePreflight = data => {
+            const blockers = (data.blocked_reasons || []).join(' / ');
+            const columns = data.mapped_insert_columns || [];
+            const missing = data.missing_insert_columns || [];
+            sampleReviewMeta.innerHTML = [
+                `mode=${data.mode || 'unknown'}`,
+                `schema=${data.schema_ready ? 'ready' : 'blocked'}`,
+                `mapped=${columns.length}`,
+                `missing=${missing.length}`,
+                `dedupe=${data.dedupe_unique_index_present ? 'yes' : 'no'}`
+            ].map(item => `<span class="market-intel-pill">${escapeHtml(item)}</span>`).join('');
+            sampleReviewBody.innerHTML = `
+                <div class="market-intel-empty mb-3">此卡檢查 payload 與 queue table 欄位相容性；頁面預設不連 DB、不寫 queue。${blockers ? `阻擋：${escapeHtml(blockers)}` : ''}</div>
+                <div class="market-intel-operation-list">
+                    <article class="market-intel-operation">
+                        <strong>mapped insert columns</strong>
+                        <small>${escapeHtml(columns.join(', ') || 'none')}</small>
+                    </article>
+                    <article class="market-intel-operation">
+                        <strong>missing columns</strong>
+                        <small>${escapeHtml(missing.join(', ') || 'none')}</small>
+                    </article>
+                    <article class="market-intel-operation">
+                        <strong>unmapped payload keys</strong>
+                        <small>${escapeHtml((data.unmapped_payload_keys || []).join(', ') || 'none')}</small>
+                    </article>
+                </div>
+            `;
+        };
+
+        const loadCandidateQueuePreflight = async () => {
+            if (!sampleReviewMeta || !sampleReviewBody || !sampleReviewInput) return;
+            let parsed;
+            try {
+                parsed = JSON.parse(sampleReviewInput.value || '{}');
+            } catch (error) {
+                sampleReviewMeta.innerHTML = '<span class="market-intel-pill">json_error</span>';
+                sampleReviewBody.innerHTML = `<div class="market-intel-empty">JSON 格式錯誤：${escapeHtml(error.message)}</div>`;
+                return;
+            }
+
+            sampleReviewBody.innerHTML = '<div class="market-intel-empty">檢查 queue writer preflight 中...</div>';
+            try {
+                const response = await fetch(sampleCandidateQueuePreflightEndpoint, {
+                    method: 'POST',
+                    credentials: 'same-origin',
+                    headers: {
+                        'Content-Type': 'application/json',
+                        'X-CSRFToken': csrfToken
+                    },
+                    body: JSON.stringify({ sample_result: parsed })
+                });
+                const data = await response.json();
+                if (!response.ok && !data.mode) throw new Error(`HTTP ${response.status}`);
+                renderCandidateQueuePreflight(data);
+            } catch (error) {
+                sampleReviewMeta.innerHTML = '<span class="market-intel-pill">error</span>';
+                sampleReviewBody.innerHTML = `<div class="market-intel-empty">queue writer preflight 檢查失敗：${escapeHtml(error.message)}</div>`;
+            }
+        };
+
         const renderSchedulerMeta = data => {
             schedulerMeta.innerHTML = [
                 `mode=${data.mode || 'unknown'}`,
@@ -3832,6 +3898,9 @@
         if (sampleCandidateQueueWriter) {
             sampleCandidateQueueWriter.addEventListener('click', loadCandidateQueueWriter);
         }
+        if (sampleCandidateQueuePreflight) {
+            sampleCandidateQueuePreflight.addEventListener('click', loadCandidateQueuePreflight);
+        }
         if (schedulerRefresh) {
             schedulerRefresh.addEventListener('click', loadScheduler);
         }

tests/test_market_intel_skeleton.py

@@ -523,6 +523,7 @@ def test_market_intel_preview_template_uses_safe_fetch_false_endpoint():
     assert "data-market-intel-sample-candidate-queue-approval" in template
     assert "data-market-intel-sample-candidate-queue-transaction" in template
     assert "data-market-intel-sample-candidate-queue-writer" in template
+    assert "data-market-intel-sample-candidate-queue-preflight" in template
     assert "data-market-intel-approval" in template
     assert "data-market-intel-approval-gates" in template
     assert "data-market-intel-deploy" in template
@@ -547,6 +548,7 @@ def test_market_intel_preview_template_uses_safe_fetch_false_endpoint():
     assert "market_intel.market_intel_manual_sample_candidate_queue_approval" in template
     assert "market_intel.market_intel_manual_sample_candidate_queue_transaction" in template
     assert "market_intel.market_intel_manual_sample_candidate_queue_writer_status" in template
+    assert "market_intel.market_intel_manual_sample_candidate_queue_writer_preflight" in template
     assert "X-CSRFToken" in template
     assert "market_intel.market_intel_scheduler_plan" in template
     assert "market_intel.market_intel_match_review_plan" in template
@@ -583,7 +585,7 @@ def test_legacy_source_bridge_default_is_planned_only():
     bridge = MarketIntelService().build_legacy_source_bridge()
 
     assert bridge["mode"] == "legacy_source_bridge_planned"
-    assert bridge["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert bridge["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert bridge["execute_requested"] is False
     assert bridge["read_only_query_executed"] is False
     assert bridge["database_connection_opened"] is False
@@ -741,7 +743,7 @@ def test_mcp_tool_contract_preview_is_read_only_and_whitelisted():
     contract = MarketIntelService().build_mcp_tool_contract()
 
     assert contract["mode"] == "mcp_tool_contract_preview"
-    assert contract["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert contract["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert contract["caller"] == "market_intel"
     assert contract["contract_ready"] is True
     assert contract["blocked_reasons"] == []
@@ -874,7 +876,7 @@ def test_mcp_activation_runbook_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "mcp_activation_runbook_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["deployment_actions_executed"] is False
     assert data["docker_command_executed"] is False
     assert data["ssh_command_executed"] is False
@@ -887,7 +889,7 @@ def test_mcp_fetch_gate_default_blocks_external_fetch():
     gate = MarketIntelService().build_mcp_fetch_gate(fetch_requested=True)
 
     assert gate["mode"] == "mcp_fetch_gate_planned"
-    assert gate["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert gate["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert gate["fetch_requested"] is True
     assert gate["manual_fetch_gate_open"] is False
     assert gate["network_request_allowed"] is False
@@ -957,7 +959,7 @@ def test_mcp_fetch_gate_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "mcp_fetch_gate_planned"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["fetch_requested"] is False
     assert data["network_request_allowed"] is False
     assert data["external_network_executed"] is False
@@ -969,7 +971,7 @@ def test_manual_sample_plan_preview_blocks_fetch_and_write():
     plan = MarketIntelService().build_manual_sample_plan()
 
     assert plan["mode"] == "manual_sample_fetch_plan_preview"
-    assert plan["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert plan["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert plan["ready_for_manual_sample_fetch"] is False
     assert plan["sample_fetch_executed"] is False
     assert plan["external_network_executed"] is False
@@ -1017,7 +1019,7 @@ def test_manual_sample_plan_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "manual_sample_fetch_plan_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["sample_fetch_executed"] is False
     assert data["external_network_executed"] is False
     assert data["database_write_executed"] is False
@@ -1028,7 +1030,7 @@ def test_manual_sample_acceptance_preview_blocks_candidate_import():
     acceptance = MarketIntelService().build_manual_sample_acceptance()
 
     assert acceptance["mode"] == "manual_sample_acceptance_preview"
-    assert acceptance["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert acceptance["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert acceptance["contract_ready"] is True
     assert acceptance["sample_result_loaded"] is False
     assert acceptance["sample_result_accepted"] is False
@@ -1070,7 +1072,7 @@ def test_manual_sample_acceptance_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "manual_sample_acceptance_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["sample_result_loaded"] is False
     assert data["candidate_import_allowed"] is False
     assert data["external_network_executed"] is False
@@ -1082,7 +1084,7 @@ def test_manual_sample_review_preview_is_planned_until_result_loaded():
     review = MarketIntelService().build_manual_sample_review()
 
     assert review["mode"] == "manual_sample_review_preview"
-    assert review["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert review["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert review["contract_ready"] is True
     assert review["sample_result_loaded"] is False
     assert review["sample_result_reviewed"] is False
@@ -1193,7 +1195,7 @@ def test_manual_sample_review_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "manual_sample_review_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["sample_result_loaded"] is False
     assert data["sample_result_reviewed"] is False
     assert data["candidate_import_allowed"] is False
@@ -1232,7 +1234,7 @@ def test_manual_sample_review_evaluation_preview_accepts_payload_without_persist
     )
 
     assert review["mode"] == "manual_sample_review_evaluation_preview"
-    assert review["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert review["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert review["review_request_type"] == "operator_posted_json"
     assert review["payload_received"] is True
     assert review["payload_valid_json_object"] is True
@@ -1294,7 +1296,7 @@ def test_manual_sample_review_evaluate_route_is_post_only_and_no_write():
 
     assert response.status_code == 200
     assert data["mode"] == "manual_sample_review_evaluation_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["payload_received"] is True
     assert data["payload_valid_json_object"] is True
     assert data["payload_persisted"] is False
@@ -1374,7 +1376,7 @@ def test_manual_sample_candidate_handoff_preview_creates_candidates_without_pers
     )
 
     assert handoff["mode"] == "manual_sample_candidate_handoff_preview"
-    assert handoff["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert handoff["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert handoff["payload_received"] is True
     assert handoff["payload_valid_json_object"] is True
     assert handoff["payload_persisted"] is False
@@ -1438,7 +1440,7 @@ def test_manual_sample_candidate_handoff_route_is_post_only_and_no_write():
 
     assert response.status_code == 200
     assert data["mode"] == "manual_sample_candidate_handoff_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["payload_received"] is True
     assert data["handoff_ready"] is True
     assert data["candidate_handoff_created"] is True
@@ -1497,7 +1499,7 @@ def test_manual_sample_candidate_queue_draft_preview_builds_review_items_without
     )
 
     assert queue_draft["mode"] == "manual_sample_candidate_queue_draft_preview"
-    assert queue_draft["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert queue_draft["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert queue_draft["payload_received"] is True
     assert queue_draft["payload_valid_json_object"] is True
     assert queue_draft["payload_persisted"] is False
@@ -1571,7 +1573,7 @@ def test_manual_sample_candidate_queue_draft_route_is_post_only_and_no_write():
 
     assert response.status_code == 200
     assert data["mode"] == "manual_sample_candidate_queue_draft_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["payload_received"] is True
     assert data["handoff_ready"] is True
     assert data["queue_draft_ready"] is True
@@ -1634,7 +1636,7 @@ def test_manual_sample_candidate_queue_approval_preview_blocks_write_and_maps_ro
     )
 
     assert approval["mode"] == "manual_sample_candidate_queue_approval_preview"
-    assert approval["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert approval["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert approval["payload_received"] is True
     assert approval["payload_valid_json_object"] is True
     assert approval["payload_persisted"] is False
@@ -1712,7 +1714,7 @@ def test_manual_sample_candidate_queue_approval_route_is_post_only_and_no_write(
 
     assert response.status_code == 200
     assert data["mode"] == "manual_sample_candidate_queue_approval_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["payload_received"] is True
     assert data["approval_preview_created"] is True
     assert data["approval_request_created"] is False
@@ -1775,7 +1777,7 @@ def test_manual_sample_candidate_queue_transaction_preview_blocks_execution():
     )
 
     assert transaction["mode"] == "manual_sample_candidate_queue_transaction_preview"
-    assert transaction["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert transaction["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert transaction["payload_received"] is True
     assert transaction["payload_valid_json_object"] is True
     assert transaction["payload_persisted"] is False
@@ -1853,7 +1855,7 @@ def test_manual_sample_candidate_queue_transaction_route_is_post_only_and_no_wri
 
     assert response.status_code == 200
     assert data["mode"] == "manual_sample_candidate_queue_transaction_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["payload_received"] is True
     assert data["transaction_preview_created"] is True
     assert data["transaction_ready"] is False
@@ -1943,6 +1945,7 @@ def test_candidate_queue_writer_cli_gate_blocks_real_write_even_with_token():
     assert status["exit_code"] == 2
     assert status["transaction_preview_summary"]["statement_count"] == 1
     assert "approval_token_valid" not in status["blocked_reasons"]
+    assert "queue_writer_preflight_ready" in status["blocked_reasons"]
     assert "queue_writer_implementation_enabled" in status["blocked_reasons"]
     assert "candidate_queue_writer_execution_not_enabled" in status["blocked_reasons"]
     assert status["safety_contract"]["refuses_api_execution"] is True
@@ -1952,6 +1955,199 @@ def test_candidate_queue_writer_cli_gate_blocks_real_write_even_with_token():
     )
 
 
+def test_candidate_queue_writer_preflight_planned_maps_payload_without_db():
+    from services.market_intel.candidate_queue_writer_preflight import (
+        build_candidate_queue_writer_preflight,
+    )
+
+    sample_result = {
+        "batch_id": "sample-batch-16",
+        "platform_code": "momo",
+        "source_key": "homepage",
+        "source_url": "https://www.momoshop.com.tw/",
+        "status": "fetched",
+        "status_code": 200,
+        "content_length": 1700,
+        "page_hash": "d" * 64,
+        "title": "MOMO 活動",
+        "diagnostics": {
+            "link_count": 1,
+            "same_host_link_count": 1,
+            "campaign_link_candidates": [
+                {
+                    "confidence_band": "high",
+                    "score": 94,
+                    "url": "https://www.momoshop.com.tw/activity/sample",
+                    "text": "品牌活動",
+                },
+            ],
+        },
+    }
+    transaction = MarketIntelService().build_manual_sample_candidate_queue_transaction(
+        sample_result=sample_result
+    )
+    preflight = build_candidate_queue_writer_preflight(
+        transaction_preview=transaction,
+        execute_requested=False,
+    )
+
+    assert preflight["mode"] == "candidate_queue_writer_preflight_planned"
+    assert preflight["execute_requested"] is False
+    assert preflight["read_only_query_executed"] is False
+    assert preflight["database_connection_opened"] is False
+    assert preflight["database_write_executed"] is False
+    assert preflight["database_commit_executed"] is False
+    assert preflight["scheduler_attached"] is False
+    assert preflight["ready_for_writer_review"] is False
+    assert preflight["ready_for_real_write"] is False
+    assert preflight["statement_count"] == 1
+    assert preflight["payload_column_map"]["metadata_json_preview"] == "metadata_json"
+    assert preflight["unmapped_payload_keys"] == []
+    assert "metadata_json" in preflight["mapped_insert_columns"]
+    assert "queue_writer_preflight_not_loaded" in preflight["blocked_reasons"]
+
+
+def test_candidate_queue_writer_preflight_sqlite_read_only_validates_columns():
+    from services.market_intel.candidate_queue_writer_preflight import (
+        build_candidate_queue_writer_preflight,
+    )
+
+    sample_result = {
+        "batch_id": "sample-batch-17",
+        "platform_code": "pchome",
+        "source_key": "homepage",
+        "source_url": "https://24h.pchome.com.tw/",
+        "status": "fetched",
+        "status_code": 200,
+        "content_length": 1800,
+        "page_hash": "e" * 64,
+        "title": "PChome 活動",
+        "diagnostics": {
+            "link_count": 1,
+            "same_host_link_count": 1,
+            "campaign_link_candidates": [
+                {
+                    "confidence_band": "medium",
+                    "score": 74,
+                    "url": "https://24h.pchome.com.tw/activity/sample",
+                    "text": "活動頁",
+                },
+            ],
+        },
+    }
+    transaction = MarketIntelService().build_manual_sample_candidate_queue_transaction(
+        sample_result=sample_result
+    )
+    engine = create_engine("sqlite:///:memory:")
+    with engine.begin() as conn:
+        conn.execute(
+            text(
+                """
+                CREATE TABLE market_alert_review_queue (
+                    id INTEGER PRIMARY KEY AUTOINCREMENT,
+                    alert_candidate_id TEXT NOT NULL UNIQUE,
+                    review_state TEXT NOT NULL DEFAULT 'draft',
+                    priority_lane TEXT NOT NULL DEFAULT 'watch',
+                    threshold_level TEXT NOT NULL,
+                    total_score FLOAT NOT NULL DEFAULT 0,
+                    evidence_bundle_id TEXT NOT NULL,
+                    dedupe_key TEXT NOT NULL,
+                    source_batch_id TEXT NOT NULL,
+                    metadata_json TEXT,
+                    created_at TEXT,
+                    updated_at TEXT
+                )
+                """
+            )
+        )
+        conn.execute(
+            text(
+                "CREATE UNIQUE INDEX ux_market_alert_review_queue_dedupe "
+                "ON market_alert_review_queue (dedupe_key)"
+            )
+        )
+
+    preflight = build_candidate_queue_writer_preflight(
+        transaction_preview=transaction,
+        execute_requested=True,
+        engine=engine,
+        database_type="sqlite",
+    )
+
+    assert preflight["mode"] == "candidate_queue_writer_preflight_read_only"
+    assert preflight["execute_requested"] is True
+    assert preflight["read_only_query_executed"] is True
+    assert preflight["database_connection_opened"] is True
+    assert preflight["database_session_created"] is False
+    assert preflight["explicit_transaction_opened"] is False
+    assert preflight["database_write_executed"] is False
+    assert preflight["database_commit_executed"] is False
+    assert preflight["scheduler_attached"] is False
+    assert preflight["table_exists"] is True
+    assert preflight["schema_ready"] is True
+    assert preflight["ready_for_writer_review"] is True
+    assert preflight["ready_for_real_write"] is False
+    assert preflight["missing_insert_columns"] == []
+    assert preflight["dedupe_unique_index_present"] is True
+    assert preflight["unmapped_payload_keys"] == []
+    assert preflight["blocked_reasons"] == [
+        "candidate_queue_writer_execution_not_enabled"
+    ]
+
+
+def test_candidate_queue_writer_preflight_route_is_post_only_and_no_write():
+    from routes.market_intel_routes import market_intel_bp
+
+    app = Flask(__name__)
+    app.secret_key = "test-secret"
+    app.register_blueprint(market_intel_bp)
+    client = app.test_client()
+    with client.session_transaction() as session:
+        session["logged_in"] = True
+
+    response = client.post(
+        "/api/market_intel/manual_sample_review/candidate_queue_writer_preflight",
+        json={
+            "sample_result": {
+                "batch_id": "sample-batch-18",
+                "platform_code": "momo",
+                "source_key": "homepage",
+                "source_url": "https://www.momoshop.com.tw/",
+                "status": "fetched",
+                "status_code": 200,
+                "content_length": 1700,
+                "page_hash": "f" * 64,
+                "title": "MOMO 活動",
+                "diagnostics": {
+                    "link_count": 1,
+                    "same_host_link_count": 1,
+                    "campaign_link_candidates": [
+                        {
+                            "confidence_band": "high",
+                            "score": 94,
+                            "url": "https://www.momoshop.com.tw/activity/sample",
+                            "text": "品牌活動",
+                        },
+                    ],
+                },
+            }
+        },
+    )
+    data = response.get_json()
+
+    assert response.status_code == 200
+    assert data["mode"] == "candidate_queue_writer_preflight_planned"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
+    assert data["execute_requested"] is False
+    assert data["read_only_query_executed"] is False
+    assert data["database_connection_opened"] is False
+    assert data["database_write_executed"] is False
+    assert data["database_commit_executed"] is False
+    assert data["scheduler_attached"] is False
+    assert data["statement_count"] == 1
+    assert data["payload_column_map"]["metadata_json_preview"] == "metadata_json"
+
+
 def test_candidate_queue_writer_status_route_never_leaks_approval_token(monkeypatch):
     from routes.market_intel_routes import market_intel_bp
 
@@ -1998,7 +2194,7 @@ def test_candidate_queue_writer_status_route_never_leaks_approval_token(monkeypa
 
     assert response.status_code == 200
     assert data["mode"] == "candidate_queue_writer_cli_blocked"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["execute_requested"] is True
     assert data["apply_real_write_requested"] is True
     assert data["approval_token_present"] is False
@@ -2048,7 +2244,7 @@ def test_scheduler_plan_preview_blocks_job_attachment():
     plan = MarketIntelService().build_scheduler_plan()
 
     assert plan["mode"] == "scheduler_attach_plan_preview"
-    assert plan["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert plan["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert plan["ready_to_attach_scheduler"] is False
     assert plan["scheduler_attached"] is False
     assert plan["scheduler_registration_executed"] is False
@@ -2086,7 +2282,7 @@ def test_scheduler_plan_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "scheduler_attach_plan_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["scheduler_registration_executed"] is False
     assert data["crawler_job_started"] is False
     assert data["external_network_executed"] is False
@@ -2097,7 +2293,7 @@ def test_match_review_plan_preview_blocks_auto_confirm():
     plan = MarketIntelService().build_match_review_plan()
 
     assert plan["mode"] == "match_review_plan_preview"
-    assert plan["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert plan["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert plan["ready_for_review_queue"] is False
     assert plan["review_queue_created"] is False
     assert plan["auto_match_executed"] is False
@@ -2133,7 +2329,7 @@ def test_match_review_plan_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "match_review_plan_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["review_queue_created"] is False
     assert data["auto_confirm_executed"] is False
     assert data["external_network_executed"] is False
@@ -2144,7 +2340,7 @@ def test_opportunity_plan_preview_blocks_alerts_and_ai_summary():
     plan = MarketIntelService().build_opportunity_plan()
 
     assert plan["mode"] == "opportunity_plan_preview"
-    assert plan["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert plan["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert plan["ready_for_opportunity_queue"] is False
     assert plan["opportunity_queue_created"] is False
     assert plan["threat_alert_dispatched"] is False
@@ -2185,7 +2381,7 @@ def test_opportunity_plan_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "opportunity_plan_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["opportunity_queue_created"] is False
     assert data["threat_alert_dispatched"] is False
     assert data["ai_summary_generated"] is False
@@ -2196,7 +2392,7 @@ def test_opportunity_scoring_plan_preview_blocks_scoring_and_alerts():
     plan = MarketIntelService().build_opportunity_scoring_plan()
 
     assert plan["mode"] == "opportunity_scoring_plan_preview"
-    assert plan["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert plan["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert plan["ready_for_scoring_job"] is False
     assert plan["scoring_job_created"] is False
     assert plan["score_calculation_executed"] is False
@@ -2244,7 +2440,7 @@ def test_opportunity_scoring_plan_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "opportunity_scoring_plan_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["scoring_job_created"] is False
     assert data["score_calculation_executed"] is False
     assert data["sample_scores_generated"] is False
@@ -2256,7 +2452,7 @@ def test_opportunity_evidence_plan_preview_blocks_queries_and_alerts():
     plan = MarketIntelService().build_opportunity_evidence_plan()
 
     assert plan["mode"] == "opportunity_evidence_plan_preview"
-    assert plan["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert plan["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert plan["ready_for_evidence_bundle"] is False
     assert plan["evidence_bundle_created"] is False
     assert plan["evidence_query_executed"] is False
@@ -2302,7 +2498,7 @@ def test_opportunity_evidence_plan_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "opportunity_evidence_plan_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["evidence_bundle_created"] is False
     assert data["evidence_query_executed"] is False
     assert data["sample_evidence_generated"] is False
@@ -2315,7 +2511,7 @@ def test_opportunity_alert_plan_preview_blocks_dispatch_and_llm_calls():
     plan = MarketIntelService().build_opportunity_alert_plan()
 
     assert plan["mode"] == "opportunity_alert_plan_preview"
-    assert plan["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert plan["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert plan["ready_for_alert_candidates"] is False
     assert plan["alert_candidate_created"] is False
     assert plan["alert_queue_created"] is False
@@ -2400,7 +2596,7 @@ def test_opportunity_alert_plan_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "opportunity_alert_plan_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["alert_candidate_created"] is False
     assert data["alert_queue_created"] is False
     assert data["review_queue_created"] is False
@@ -2478,7 +2674,7 @@ def test_mcp_deploy_preflight_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "mcp_external_deploy_preflight_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["deployment_actions_executed"] is False
     assert data["docker_command_executed"] is False
     assert data["ssh_command_executed"] is False
@@ -2493,7 +2689,7 @@ def test_mcp_readiness_default_is_planned_only(monkeypatch):
     readiness = MarketIntelService().build_mcp_readiness()
 
     assert readiness["mode"] == "mcp_readiness_planned"
-    assert readiness["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert readiness["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert readiness["execute_requested"] is False
     assert readiness["router_enabled"] is False
     assert readiness["external_mcp_complete"] is False
@@ -2890,6 +3086,7 @@ def test_deployment_readiness_reports_app_only_release_gate():
     assert readiness["checks"]["manual_sample_candidate_queue_approval_post_safe"] is True
     assert readiness["checks"]["manual_sample_candidate_queue_transaction_post_safe"] is True
     assert readiness["checks"]["candidate_queue_writer_cli_status_safe"] is True
+    assert readiness["checks"]["candidate_queue_writer_preflight_planned_safe"] is True
     assert readiness["checks"]["match_review_plan_preview_safe"] is True
     assert readiness["checks"]["opportunity_plan_preview_safe"] is True
     assert readiness["checks"]["opportunity_scoring_plan_preview_safe"] is True
@@ -3223,6 +3420,30 @@ def test_deployment_readiness_reports_app_only_release_gate():
         readiness["candidate_queue_writer_cli_status"]["scheduler_attached"]
         is False
     )
+    assert (
+        readiness["candidate_queue_writer_preflight"]["mode"]
+        == "candidate_queue_writer_preflight_planned"
+    )
+    assert (
+        readiness["candidate_queue_writer_preflight"]["read_only_query_executed"]
+        is False
+    )
+    assert (
+        readiness["candidate_queue_writer_preflight"]["database_connection_opened"]
+        is False
+    )
+    assert (
+        readiness["candidate_queue_writer_preflight"]["database_write_executed"]
+        is False
+    )
+    assert (
+        readiness["candidate_queue_writer_preflight"]["database_commit_executed"]
+        is False
+    )
+    assert (
+        readiness["candidate_queue_writer_preflight"]["scheduler_attached"]
+        is False
+    )
     assert readiness["scheduler_plan"]["scheduler_registration_executed"] is False
     assert readiness["scheduler_plan"]["crawler_job_started"] is False
     assert readiness["scheduler_plan"]["database_write_executed"] is False
@@ -3327,7 +3548,7 @@ def test_migration_apply_drill_planned_is_safe_and_manual_only():
     drill = MarketIntelService().build_migration_apply_drill()
 
     assert drill["mode"] == "migration_apply_drill_preview"
-    assert drill["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert drill["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert drill["execute_requested"] is False
     assert drill["schema_state"] == "planned_no_db_probe"
     assert drill["drill_ready_for_operator_review"] is True
@@ -3442,7 +3663,7 @@ def test_migration_apply_drill_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "migration_apply_drill_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["execute_requested"] is False
     assert data["migration_executed"] is False
     assert data["rollback_executed"] is False
@@ -3454,7 +3675,7 @@ def test_migration_catalog_review_planned_is_safe_and_diagnostic():
     review = MarketIntelService().build_migration_catalog_review()
 
     assert review["mode"] == "migration_catalog_review_preview"
-    assert review["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert review["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert review["execute_requested"] is False
     assert review["catalog_state"] == "planned_no_probe"
     assert review["seed_state"] == "planned_no_probe"
@@ -3569,7 +3790,7 @@ def test_migration_catalog_review_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "migration_catalog_review_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["execute_requested"] is False
     assert data["catalog_state"] == "planned_no_probe"
     assert data["migration_executed"] is False
@@ -3582,7 +3803,7 @@ def test_migration_live_smoke_planned_is_preview_only():
     smoke = MarketIntelService().build_migration_live_smoke()
 
     assert smoke["mode"] == "migration_live_smoke_preview"
-    assert smoke["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert smoke["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert smoke["execute_requested"] is False
     assert smoke["smoke_result"] == "planned_no_execution"
     assert smoke["live_smoke_passed"] is False
@@ -3644,7 +3865,7 @@ def test_migration_live_smoke_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "migration_live_smoke_preview"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["execute_requested"] is False
     assert data["smoke_result"] == "planned_no_execution"
     assert data["migration_executed"] is False
@@ -3657,7 +3878,7 @@ def test_live_db_inventory_planned_is_preview_only():
     inventory = MarketIntelService().build_live_db_inventory()
 
     assert inventory["mode"] == "live_db_inventory_planned"
-    assert inventory["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert inventory["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert inventory["execute_requested"] is False
     assert inventory["read_only_query_executed"] is False
     assert inventory["database_connection_opened"] is False
@@ -3801,7 +4022,7 @@ def test_live_db_inventory_route_is_preview_only():
 
     assert response.status_code == 200
     assert data["mode"] == "live_db_inventory_planned"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["execute_requested"] is False
     assert data["read_only_query_executed"] is False
     assert data["database_write_executed"] is False
@@ -4028,7 +4249,7 @@ def test_candidate_queue_writer_cli_script_outputs_blocked_gate(tmp_path):
 
     assert result.returncode == 0
     assert data["mode"] == "candidate_queue_writer_cli_blocked"
-    assert data["phase"] == "phase_55_candidate_queue_writer_cli_gate"
+    assert data["phase"] == "phase_56_candidate_queue_writer_preflight"
     assert data["execute_requested"] is False
     assert data["apply_real_write_requested"] is False
     assert data["writes_executed"] is False