fix(cd-blocker-2): setup_test_schema.sql 補 KM 欄位（解 CD 真實 root cause）

## 之前 c5b18101 修錯地方

我加 db/base.py:init_db() ALTER 沒解問題。**CI 不跑 init_db()**。

## 真實 CD 流程

`.gitea/workflows/cd.yaml` Integration Tests step：
1. 啟動臨時 `pg-test-b5` 容器（fresh PG）
2. `psql -f tests/integration/setup_test_schema.sql` 建表
3. 跑 pytest tests/integration/test_b5_core_flows.py

setup_test_schema.sql 的 `knowledge_entries` 表沒有
`related_approval_id` + `path_type` 欄位 → INSERT 失敗。

## 修法

setup_test_schema.sql:110 `CREATE TABLE knowledge_entries` 補：
- related_approval_id VARCHAR(64)
- path_type VARCHAR(50)
- uix_knowledge_incident_path partial unique index
- ix_knowledge_related_approval partial index

## 預期效果

CD #1119 (本 commit) 應該成功。
解鎖 4 個 stuck commit (1114-1118) 的部署 backlog。
fb0c72db 推翻 A2 DIAGNOSE Ollama primary 終於上 prod。

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

apps/api/tests/integration/setup_test_schema.sql

@@ -119,11 +119,24 @@ CREATE TABLE IF NOT EXISTS knowledge_entries (
     related_incident_id VARCHAR,
     related_playbook_id VARCHAR,
     symptoms_hash VARCHAR,
+    -- 2026-04-29 ogt + Claude Opus 4.7: M4 KMWriter 反查鏈 + 冪等補欄
+    -- 解 CD #1115-1118 全 failure：column "related_approval_id" does not exist
+    -- 對應 commit c22e5f33 KMWriter ORM 加的欄位
+    related_approval_id VARCHAR(64),
+    path_type VARCHAR(50),
     view_count INTEGER DEFAULT 0,
     created_by VARCHAR,
     created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
     updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
 );
+-- M3 冪等 unique index (incident_id + path_type)
+CREATE UNIQUE INDEX IF NOT EXISTS uix_knowledge_incident_path
+    ON knowledge_entries(related_incident_id, path_type)
+    WHERE related_incident_id IS NOT NULL AND path_type IS NOT NULL;
+-- M4 反查鏈 partial index
+CREATE INDEX IF NOT EXISTS ix_knowledge_related_approval
+    ON knowledge_entries(related_approval_id)
+    WHERE related_approval_id IS NOT NULL;
 
 CREATE TABLE IF NOT EXISTS rag_chunks (
     id UUID PRIMARY KEY DEFAULT gen_random_uuid(),