fix(drift-card): Drift Diff HTTP 400 — item-by-item 累計長度避免切斷 HTML

統帥回報 14:18 點 [查看 Diff] 收到 'Drift Diff 查詢失敗: HTTP error: 400'

真因 (telegram_gateway.py:2087 _send_drift_diff_detail):
  - report_id=7ffe78ae 有 48 items,單筆 git_value 最長 1794 字 (env array)
  - 累計 _full 遠超 4096,執行 _full[:3950] 截斷
  - 截斷可能切在 HTML tag 中間 (<code>... 或 &lt; entity 中間)
  - Telegram parse_mode='HTML' 拒絕不完整 HTML → 400

修復:
  - item-by-item 累計長度,單個 item 算 _block 長度+1
  - 預留 3800 上限 (4096 - 250 buffer 給 header + '… 還有 X 項' 提示)
  - 確保 _full 永遠是完整 HTML 結構

驗證: 下次 drift report 出現 + 統帥點 [查看 Diff] 應正常顯示 (本 session 的下個 cycle)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/api/src/services/telegram_gateway.py

@@ -2100,26 +2100,44 @@ class TelegramGateway:
                 })
                 return
 
-            _lines = [f"📊 <b>完整 Drift Diff</b> — <code>{html.escape(report_id)}</code>"]
+            # 2026-04-19 ogt + Claude Opus 4.7: 修 HTTP 400 真因
-            _lines.append(f"Namespace: <code>{html.escape(_rpt.namespace)}</code>")
+            # 原邏輯: _full[:3950] 切在 HTML tag/entity 中間 → Telegram parse_mode HTML 拒絕
-            _lines.append(f"HIGH×{_rpt.high_count}  MEDIUM×{_rpt.medium_count}  INFO×{_rpt.info_count}")
+            # 修法: item-by-item 累計長度,超過 3800 就停,確保完整 HTML 結構
-            _lines.append("━" * 20)
+            #       (3800 留 250 buffer 給 header + 截斷提示)
-            for i, _item in enumerate(_rpt.items[:50], 1):
+            _MAX_LEN = 3800
+
+            _header = [
+                f"📊 <b>完整 Drift Diff</b> — <code>{html.escape(report_id)}</code>",
+                f"Namespace: <code>{html.escape(_rpt.namespace)}</code>",
+                f"HIGH×{_rpt.high_count}  MEDIUM×{_rpt.medium_count}  INFO×{_rpt.info_count}",
+                "━" * 20,
+            ]
+            _lines = list(_header)
+            _used_len = sum(len(s) + 1 for s in _header)
+            _shown = 0
+
+            for _item in _rpt.items:
                 _level = getattr(_item.drift_level, "value", str(_item.drift_level))
                 _emoji = "🔴" if _level == "high" else ("🟡" if _level == "medium" else "⚪")
                 _field = (_item.field_path or "")[:80]
                 _git = str(_item.git_value)[:40] if _item.git_value is not None else "(未設)"
                 _k8s = str(_item.actual_value)[:40] if _item.actual_value is not None else "(未設)"
-                _lines.append(f"{_emoji} <b>{html.escape(_field)}</b>")
+                _block = (
-                _lines.append(f"   Git: <code>{html.escape(_git)}</code>")
+                    f"{_emoji} <b>{html.escape(_field)}</b>\n"
-                _lines.append(f"   K8s: <code>{html.escape(_k8s)}</code>")
+                    f"   Git: <code>{html.escape(_git)}</code>\n"
-            if len(_rpt.items) > 50:
+                    f"   K8s: <code>{html.escape(_k8s)}</code>"
-                _lines.append(f"… 還有 {len(_rpt.items) - 50} 項未顯示")
+                )
+                if _used_len + len(_block) + 1 > _MAX_LEN:
+                    break
+                _lines.append(_block)
+                _used_len += len(_block) + 1
+                _shown += 1
+
+            _remaining = len(_rpt.items) - _shown
+            if _remaining > 0:
+                _lines.append(f"… 還有 {_remaining} 項未顯示")
 
             _full = "\n".join(_lines)
-            # Telegram 訊息上限 4096 字元
-            if len(_full) > 4000:
-                _full = _full[:3950] + "\n… (截斷)"
 
             await self._send_request("sendMessage", {
                 "chat_id": settings.OPENCLAW_TG_CHAT_ID,