fix(api): Review #2 技術債清理 — I1/S1/S2/S3 全數修正

I1: error_type 欄位補全
- AnomalyCounter.derive_key_from_incident() 新增
  從 signal.labels 提取 reason/error_type，確保四欄位完整

S1: 三處 signature 建構邏輯統一
- auto_repair_service._derive_anomaly_key() → 委託 derive_key_from_incident()
- approval_execution._get_anomaly_key_from_approval() → 同上
- incident_service.resolve_incident() B4 → 同上
- 消除 3 處重複的 signature 建構程式碼

S2: Redis Pipeline 批次查詢
- get_all_disposition_stats() 從 N+1 hgetall 改為 2 次 Pipeline
- Pipeline 1: 批次 hgetall 所有 disposition key
- Pipeline 2: 批次 hget metadata (alert_name)
- 效能從 O(2N) Redis round-trip 降至 O(2)

S3: auto_repair.py get_incident AttributeError 修復
- get_incident() → get_from_working_memory() (pre-existing bug)

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

apps/api/src/api/v1/auto_repair.py

@@ -81,7 +81,7 @@ async def evaluate_auto_repair(incident_id: str) -> EvaluateResponse:
     """
     # 取得 Incident
     incident_service = get_incident_service()
-    incident = await incident_service.get_incident(incident_id)
+    incident = await incident_service.get_from_working_memory(incident_id)
 
     if not incident:
         raise HTTPException(
@@ -116,7 +116,7 @@ async def execute_auto_repair(request: ExecuteRequest) -> ExecuteResponse:
     """
     # 取得 Incident
     incident_service = get_incident_service()
-    incident = await incident_service.get_incident(request.incident_id)
+    incident = await incident_service.get_from_working_memory(request.incident_id)
 
     if not incident:
         raise HTTPException(

apps/api/src/services/anomaly_counter.py

@@ -118,6 +118,30 @@ class AnomalyCounter:
     def __init__(self, redis_client: redis.Redis) -> None:
         self.redis = redis_client
 
+    @staticmethod
+    def derive_key_from_incident(incident) -> str | None:
+        """
+        從 Incident 推導 anomaly_key，統一使用 hash_signature() 四欄位。
+        2026-04-07 Claude Code: I1+S1 Fix — 統一推導邏輯，補全 error_type
+
+        Args:
+            incident: Incident model (需有 signals, affected_services)
+
+        Returns:
+            anomaly_key (16 char hex) or None
+        """
+        if not incident.signals:
+            return None
+        signal = incident.signals[0]
+        labels = signal.labels or {}
+        signature = {
+            "alert_name": signal.alert_name,
+            "service": incident.affected_services[0] if incident.affected_services else "",
+            "namespace": labels.get("namespace", ""),
+            "error_type": labels.get("reason", labels.get("error_type", "")),
+        }
+        return AnomalyCounter.hash_signature(signature)
+
     @staticmethod
     def hash_signature(signature: dict) -> str:
         """
@@ -446,15 +470,34 @@ class AnomalyCounter:
         by_anomaly: list[dict] = []
 
         try:
+            # S2 Fix: 使用 Pipeline 批次查詢，消除 N+1 問題
             pattern = f"{self.PREFIX_DISPOSITION}*"
             keys: list = []
             async for key in self.redis.scan_iter(match=pattern, count=100):
                 keys.append(key)
 
+            if not keys:
+                return total_summary, by_anomaly
+
+            # Pipeline 1: 批次取得所有 disposition hash
+            pipe = self.redis.pipeline(transaction=False)
+            for key in keys:
+                pipe.hgetall(key)
+            results = await pipe.execute()
+
+            # Pipeline 2: 批次取得所有 metadata (alert_name)
+            anomaly_keys_str = []
             for key in keys:
-                raw = await self.redis.hgetall(key)
                 key_str = key.decode() if isinstance(key, bytes) else key
-                anomaly_key = key_str.replace(self.PREFIX_DISPOSITION, "")
+                anomaly_keys_str.append(key_str.replace(self.PREFIX_DISPOSITION, ""))
+
+            meta_pipe = self.redis.pipeline(transaction=False)
+            for ak in anomaly_keys_str:
+                meta_pipe.hget(f"{self.PREFIX_METADATA}{ak}", "signature")
+            meta_results = await meta_pipe.execute()
+
+            for i, raw in enumerate(results):
+                anomaly_key = anomaly_keys_str[i]
 
                 d = {
                     "auto_repair": int(raw.get(b"auto_repair", raw.get("auto_repair", 0))),
@@ -467,11 +510,9 @@ class AnomalyCounter:
                 for k in total_summary:
                     total_summary[k] += d[k]
 
-                # 嘗試取得 alert_name
                 alert_name = ""
                 try:
-                    meta_key = f"{self.PREFIX_METADATA}{anomaly_key}"
-                    meta_raw = await self.redis.hget(meta_key, "signature")
+                    meta_raw = meta_results[i]
                     if meta_raw:
                         sig = json.loads(meta_raw)
                         alert_name = sig.get("alert_name", "")

apps/api/src/services/approval_execution.py

@@ -219,11 +219,8 @@ class ApprovalExecutionService:
 
     async def _get_anomaly_key_from_approval(self, approval: ApprovalRequest) -> str | None:
         """
-        從 approval → incident → anomaly_signature → hash。
-        2026-04-07 Claude Code: Sprint 4 B3
-
-        Returns:
-            anomaly_key or None if not derivable
+        從 approval → incident → anomaly_key。
+        2026-04-07 Claude Code: I1+S1 Fix — 委託 AnomalyCounter.derive_key_from_incident()
         """
         try:
             if not approval.incident_id:
@@ -231,18 +228,10 @@ class ApprovalExecutionService:
             from src.services.incident_service import get_incident_service
             incident_service = get_incident_service()
             incident = await incident_service.get_from_working_memory(approval.incident_id)
-            if not incident or not incident.signals:
+            if not incident:
                 return None
-            # 從第一個 signal 建立 anomaly signature
-            # P0-1 Fix: namespace 從 signal.labels 取，非 getattr
-            signal = incident.signals[0]
-            signature = {
-                "alert_name": signal.alert_name,
-                "service": incident.affected_services[0] if incident.affected_services else "",
-                "namespace": signal.labels.get("namespace", "") if signal.labels else "",
-            }
             from src.services.anomaly_counter import AnomalyCounter
-            return AnomalyCounter.hash_signature(signature)
+            return AnomalyCounter.derive_key_from_incident(incident)
         except Exception as e:
             logger.warning("get_anomaly_key_from_approval_failed", error=str(e))
             return None

apps/api/src/services/auto_repair_service.py

@@ -485,22 +485,11 @@ class AutoRepairService:
     @staticmethod
     def _derive_anomaly_key(incident: Incident) -> str | None:
         """
-        從 Incident 推導 anomaly_key，統一使用 AnomalyCounter.hash_signature()。
-        2026-04-07 Claude Code: P0-1 Fix — 統一 hash 演算法
-
-        Returns:
-            anomaly_key or None if not derivable
+        從 Incident 推導 anomaly_key。
+        2026-04-07 Claude Code: I1+S1 Fix — 委託 AnomalyCounter.derive_key_from_incident()
         """
-        if not incident.signals:
-            return None
-        signal = incident.signals[0]
-        signature = {
-            "alert_name": signal.alert_name,
-            "service": incident.affected_services[0] if incident.affected_services else "",
-            "namespace": signal.labels.get("namespace", "") if signal.labels else "",
-        }
         from src.services.anomaly_counter import AnomalyCounter
-        return AnomalyCounter.hash_signature(signature)
+        return AnomalyCounter.derive_key_from_incident(incident)
 
     def _extract_symptoms(self, incident: Incident) -> SymptomPattern:
         """從 Incident 提取症狀模式"""

apps/api/src/services/incident_service.py

@@ -693,21 +693,13 @@ class IncidentService:
             logger.exception("kb_extract_task_create_failed", incident_id=incident_id)
 
         # 2026-04-07 Claude Code: Sprint 4 B4 — 手動處理推斷
-        # 若 resolved 但沒有系統修復紀錄 → manual_resolved
+        # I1+S1 Fix: 委託 derive_key_from_incident() 統一推導
         try:
             from src.services.anomaly_counter import AnomalyCounter, get_anomaly_counter
             counter = get_anomaly_counter()
-            if incident.signals:
-                # P0-1 Fix: namespace 從 signal.labels 取
-                signal = incident.signals[0]
-                signature = {
-                    "alert_name": signal.alert_name,
-                    "service": incident.affected_services[0] if incident.affected_services else "",
-                    "namespace": signal.labels.get("namespace", "") if signal.labels else "",
-                }
-                anomaly_key = AnomalyCounter.hash_signature(signature)
+            anomaly_key = AnomalyCounter.derive_key_from_incident(incident)
+            if anomaly_key:
                 disposition = await counter.get_disposition_stats(anomaly_key)
-                # 排除法: 如果已有 auto/human/cold_start 紀錄，代表系統已處理
                 has_system_resolution = (
                     disposition["auto_repair"] > 0
                     or disposition["human_approved"] > 0