feat(sweeper): 新增 Incident Analysis Sweeper — 自動觸發未分析 Incident AI 決策

Gap修復:
  Signal Worker 創建 Incident 後，AI 分析只在 GET /api/v1/incidents 被呼叫時觸發
  若前端無人訪問，新 Incident 永遠沒有 AI 分析與 Telegram 通知

解法:
  新增 src/jobs/incident_analysis_sweeper.py
  每 90 秒掃描無 decision token 的 INVESTIGATING incidents
  自動背景觸發 get_or_create_decision() — Semaphore(3) 限流，每批最多 5 筆
  main.py lifespan 啟動時 asyncio.create_task() 掛載

2026-04-16 Claude Sonnet 4.6 Asia/Taipei

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

apps/api/src/jobs/incident_analysis_sweeper.py

@@ -0,0 +1,106 @@
+"""
+Incident Analysis Sweeper — 自動觸發 INVESTIGATING 事件 AI 分析
+================================================================
+問題背景:
+  Signal Worker 創建 Incident 後，AI 分析 (decision_manager) 原本只在
+  GET /api/v1/incidents 被呼叫時才觸發 (背景 fire-and-forget)。
+  若前端沒人看或 Telegram Bot 未呼叫該端點，新 Incident 永遠沒有 AI 分析。
+
+解法:
+  每 90 秒掃描 INVESTIGATING 狀態且無 decision token 的 Incident，
+  自動在背景觸發 get_or_create_decision()。
+
+限流:
+  Semaphore(3) — 避免並發壓垮 OPENCLAW_NEMO/Ollama
+  每批最多 5 個 incident，避免啟動雪崩
+
+2026-04-16 Claude Sonnet 4.6 Asia/Taipei
+"""
+from __future__ import annotations
+
+import asyncio
+
+import structlog
+
+from src.models.incident import Incident, IncidentStatus, Severity
+
+logger = structlog.get_logger(__name__)
+
+_SWEEP_INTERVAL_SEC = 90      # 每 90 秒掃一次
+_MAX_BATCH = 5                # 每批最多 5 個
+_SEMAPHORE_LIMIT = 3          # 最多 3 個並發 AI 分析
+
+
+async def run_incident_analysis_sweeper() -> None:
+    """
+    永久迴圈：每 90 秒自動為未分析的 INVESTIGATING Incident 觸發 AI 分析。
+    由 main.py lifespan 透過 asyncio.create_task() 啟動。
+    """
+    logger.info("incident_analysis_sweeper_started", interval_sec=_SWEEP_INTERVAL_SEC)
+    sem = asyncio.Semaphore(_SEMAPHORE_LIMIT)
+
+    while True:
+        try:
+            await _sweep_once(sem)
+        except Exception as e:
+            logger.warning("incident_analysis_sweeper_error", error=str(e))
+
+        await asyncio.sleep(_SWEEP_INTERVAL_SEC)
+
+
+async def _sweep_once(sem: asyncio.Semaphore) -> None:
+    """
+    執行一次掃描：找出沒有 decision token 的 INVESTIGATING incidents，
+    在背景觸發 AI 分析。
+    """
+    from src.services.decision_manager import get_decision_manager
+    from src.services.incident_service import get_incident_service
+    from src.core.redis_client import get_redis
+
+    redis = get_redis()
+    incident_service = get_incident_service()
+    dm = get_decision_manager()
+
+    # 取得所有 INVESTIGATING incidents
+    try:
+        incidents: list[Incident] = await incident_service.get_active_incidents()
+    except Exception as e:
+        logger.warning("sweeper_get_incidents_failed", error=str(e))
+        return
+
+    if not incidents:
+        return
+
+    # 找出沒有 decision token 的
+    unanalyzed = []
+    for incident in incidents:
+        token_key = f"decision:{incident.incident_id}"
+        if not await redis.exists(token_key):
+            unanalyzed.append(incident)
+
+    if not unanalyzed:
+        return
+
+    # 限制每批
+    batch = unanalyzed[:_MAX_BATCH]
+    logger.info(
+        "sweeper_triggering_analysis",
+        total_unanalyzed=len(unanalyzed),
+        batch_size=len(batch),
+    )
+
+    async def _analyze(incident: Incident) -> None:
+        async with sem:
+            try:
+                timeout = 120.0 if incident.severity in (Severity.P0, Severity.P1) else 180.0
+                await dm.get_or_create_decision(incident=incident, timeout_sec=timeout)
+                logger.info("sweeper_analysis_done", incident_id=incident.incident_id)
+            except Exception as e:
+                logger.warning(
+                    "sweeper_analysis_failed",
+                    incident_id=incident.incident_id,
+                    error=str(e),
+                )
+
+    tasks = [asyncio.create_task(_analyze(inc)) for inc in batch]
+    await asyncio.gather(*tasks, return_exceptions=True)

apps/api/src/main.py

@@ -334,6 +334,17 @@ async def lifespan(_app: FastAPI) -> AsyncGenerator[None, None]:
     except Exception as e:
         logger.warning("stale_ready_tokens_resend_schedule_failed", error=str(e))
 
+    # 2026-04-16 Claude Sonnet 4.6: 自動 AI 分析 Sweeper（每 90 秒）
+    # 修復核心 Gap：Signal Worker 創建 Incident 後無人觸發 AI 分析
+    # 除非有人呼叫 GET /api/v1/incidents，否則 Incident 永遠沒有決策
+    # Sweeper 定期掃描無 decision token 的 INVESTIGATING incidents → 背景觸發
+    try:
+        from src.jobs.incident_analysis_sweeper import run_incident_analysis_sweeper
+        asyncio.create_task(run_incident_analysis_sweeper())
+        logger.info("incident_analysis_sweeper_scheduled", interval_sec=90)
+    except Exception as e:
+        logger.warning("incident_analysis_sweeper_schedule_failed", error=str(e))
+
     # ADR-076 Task 4: 每日 08:00 台北時間自動日度巡檢報告
     # 2026-04-14 Claude Haiku 4.5 Asia/Taipei
     try: