feat(trust): ADR-088 Trust Score 持久化 — L4 自動放行核心

TrustScoreManager 從記憶體升級為 PostgreSQL 持久化，
Pod 重啟後信任分數不再歸零，AI 能真正累積到 L4 自動放行門檻。

變更:
- migrations/adr088_trust_score_persistence.sql: trust_records 表
- db/models.py: TrustRecordDB ORM model
- repositories/interfaces.py: ITrustRepository Protocol
- repositories/trust_repository.py: PG upsert ON CONFLICT DO UPDATE
- services/trust_engine.py: bulk_load() 啟動 warm-up
- services/learning_service.py: _persist_trust() + 2 call sites
- main.py: 啟動時 load_all() → bulk_load()

流程: 批准 5 次 → score=5 寫入 DB → Pod 重啟 → warm-up 讀回
      → evaluate_adjusted_risk MEDIUM→LOW → 自動執行

2026-04-17 ogt + Claude Sonnet 4.6（亞太）: ADR-088

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/api/src/services/trust_engine.py

@@ -362,6 +362,46 @@ class TrustScoreManager:
             record.score = 0
         logger.warning("[TrustEngine] All trust scores reset!")
 
+    def bulk_load(self, records: list[dict]) -> int:
+        """
+        從 DB 批量載入 trust records 到記憶體（啟動 warm-up 用）。
+
+        ADR-088: Pod 重啟後從 PostgreSQL 恢復信任分數，
+        確保 AI 不會因重啟而失憶歸零。
+
+        Args:
+            records: list[dict] — 每筆含 action_pattern, score,
+                     total_approvals, total_rejections,
+                     last_approval_by, last_approval_at,
+                     last_rejection_by, last_rejection_at
+
+        Returns:
+            int: 載入筆數
+
+        2026-04-17 ogt + Claude Sonnet 4.6（亞太）: ADR-088
+        """
+        loaded = 0
+        for r in records:
+            pattern = r.get("action_pattern")
+            if not pattern:
+                continue
+            record = TrustRecord(
+                action_pattern=pattern,
+                score=r.get("score", 0),
+                total_approvals=r.get("total_approvals", 0),
+                total_rejections=r.get("total_rejections", 0),
+                last_approval_by=r.get("last_approval_by"),
+                last_approval_at=r.get("last_approval_at"),
+                last_rejection_by=r.get("last_rejection_by"),
+                last_rejection_at=r.get("last_rejection_at"),
+            )
+            self._records[pattern] = record
+            loaded += 1
+
+        if loaded:
+            logger.info(f"[TrustEngine] Warm-up: loaded {loaded} trust records from DB")
+        return loaded
+
 
 # ==================== Pattern Matching Utilities ====================