fix(worker): dedicated Redis pool with unlimited timeout for XREADGROUP

Root cause: Worker shared Redis pool with API (socket_timeout=5s),
but XREADGROUP blocks for 5s causing timeout errors every cycle.

Fix:
- Add init_worker_redis_pool() with socket_timeout=None
- Worker now uses get_worker_redis() for XREADGROUP operations
- API continues using get_redis() with short timeout

Also destroyed 50 zombie consumers via:
  XGROUP DESTROY stream:awoooi_signals awoooi_workers

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

apps/api/src/core/redis_client.py

@@ -27,11 +27,17 @@ logger = structlog.get_logger(__name__)
 
 
 # =============================================================================
-# Connection Pool
+# Connection Pool (API 用 - 短超時)
 # =============================================================================
 
 _redis_pool: redis.Redis | None = None
 
+# =============================================================================
+# Worker 專屬連線池 (長超時，用於 XREADGROUP 阻塞操作)
+# =============================================================================
+
+_worker_redis_pool: redis.Redis | None = None
+
 
 async def init_redis_pool() -> redis.Redis:
     """
@@ -83,7 +89,7 @@ async def close_redis_pool() -> None:
 
 def get_redis() -> redis.Redis:
     """
-    取得 Redis 連線
+    取得 Redis 連線 (API 用，短超時)
 
     Raises:
         RuntimeError: 若連線池未初始化
@@ -93,6 +99,73 @@ def get_redis() -> redis.Redis:
     return _redis_pool
 
 
+# =============================================================================
+# Worker 專屬連線池 (長超時)
+# =============================================================================
+
+
+async def init_worker_redis_pool() -> redis.Redis:
+    """
+    初始化 Worker 專屬 Redis 連線池
+
+    統帥鐵律 2026-03-23:
+    - Worker 使用 XREADGROUP 阻塞操作，需要長超時
+    - 絕對禁止與 API 共用短超時連線池
+    - socket_timeout=None 表示無限等待
+    """
+    global _worker_redis_pool
+
+    if _worker_redis_pool is not None:
+        return _worker_redis_pool
+
+    _worker_redis_pool = redis.from_url(
+        settings.REDIS_URL,
+        encoding="utf-8",
+        decode_responses=True,
+        max_connections=5,  # Worker 不需要太多連線
+        socket_timeout=None,  # 無限等待 (XREADGROUP 阻塞操作)
+        socket_connect_timeout=10.0,  # 連線超時仍需設定
+    )
+
+    # 測試連線
+    try:
+        await _worker_redis_pool.ping()
+        logger.info(
+            "worker_redis_pool_initialized",
+            url=settings.REDIS_URL.split("@")[-1],
+            socket_timeout="None (unlimited)",
+        )
+    except redis.ConnectionError as e:
+        logger.error("worker_redis_connection_failed", error=str(e))
+        raise
+
+    return _worker_redis_pool
+
+
+async def close_worker_redis_pool() -> None:
+    """
+    關閉 Worker 專屬 Redis 連線池
+    """
+    global _worker_redis_pool
+
+    if _worker_redis_pool is not None:
+        await _worker_redis_pool.close()
+        _worker_redis_pool = None
+        logger.info("worker_redis_pool_closed")
+
+
+def get_worker_redis() -> redis.Redis:
+    """
+    取得 Worker 專屬 Redis 連線 (長超時，用於 XREADGROUP)
+
+    Raises:
+        RuntimeError: 若連線池未初始化
+    """
+    if _worker_redis_pool is None:
+        raise RuntimeError("Worker Redis pool not initialized. Call init_worker_redis_pool() first.")
+    return _worker_redis_pool
+
+
 # =============================================================================
 # Distributed Lock (分散式鎖)
 # =============================================================================

apps/api/src/workers/signal_worker.py

@@ -26,7 +26,7 @@ from typing import Any
 
 import structlog
 
-from src.core.redis_client import get_redis
+from src.core.redis_client import get_redis, get_worker_redis
 from src.services.incident_engine import get_incident_engine
 
 logger = structlog.get_logger(__name__)
@@ -149,8 +149,12 @@ class SignalWorker:
         主消費循環
 
         XREADGROUP 阻塞等待新訊息，處理後 XACK。
+
+        統帥鐵律 2026-03-23:
+        - 使用 Worker 專屬 Redis 連線 (無超時限制)
+        - 絕對禁止使用 API 共用的短超時連線
         """
-        redis_client = get_redis()
+        redis_client = get_worker_redis()  # Worker 專屬長連線
 
         while self._running:
             try:
@@ -321,7 +325,7 @@ async def _main() -> None:
 
     # Initialize settings first (loads env vars)
     from src.core.config import settings  # noqa: F401
-    from src.core.redis_client import init_redis_pool, close_redis_pool
+    from src.core.redis_client import init_redis_pool, close_redis_pool, init_worker_redis_pool, close_worker_redis_pool
 
     logger.info(
         "signal_worker_standalone_starting",
@@ -329,8 +333,9 @@ async def _main() -> None:
         redis_url=settings.REDIS_URL.split("@")[-1] if settings.REDIS_URL else "N/A",
     )
 
-    # Initialize Redis
+    # Initialize Redis (API pool + Worker 專屬長連線池)
     await init_redis_pool()
+    await init_worker_redis_pool()  # Worker 專屬，無超時限制
 
     # Write health files for K8s probes
     await _write_health_files()
@@ -354,6 +359,7 @@ async def _main() -> None:
     # Graceful shutdown
     logger.info("signal_worker_shutting_down")
     await worker.stop()
+    await close_worker_redis_pool()  # 關閉 Worker 專屬連線
     await close_redis_pool()
 
     # Remove health files