feat(B-RED): Zentraler Redis Pool — cache.py, monitoring.py, worker.py auf get_redis() umgestellt

B-RED: 5 direkte aioredis.from_url() Konstruktoren auf get_redis() umgestellt
- cache.py: get_cache() delegiert auf get_redis(), _cache_redis Singleton entfernt
- monitoring.py: check_redis() und check_worker() nutzen get_redis()
- worker.py: _acquire_cron_lock() und _release_cron_lock() nutzen get_redis()
- 0 verbleibende direkte aioredis.from_url() außerhalb auth.py

B-RED-TEST: 8 Tests in test_redis_pool.py — alle grün
- Singleton, get_cache delegation, SET/GET, parallel, reset, no-direct-from_url checks

app/core/worker.py

@@ -20,7 +20,6 @@ logger = logging.getLogger(__name__)
 # on every replica.  We use a short-lived Redis SET NX lock per cron call
 # so only one replica actually executes the job.
 
-import redis.asyncio as aioredis  # noqa: E402
 import uuid  # noqa: E402
 
 
@@ -31,33 +30,29 @@ async def _acquire_cron_lock(job_name: str, ttl_seconds: int = 120) -> str | Non
     replica already holds the lock.  The lock auto-expires after
     *ttl_seconds* to avoid deadlocks if a worker crashes mid-job.
     """
-    settings = get_settings()
-    client = aioredis.from_url(settings.redis_url)
+    from app.core.auth import get_redis
+
+    client = get_redis()
     token = str(uuid.uuid4())
     lock_key = f"leocrm:cron_lock:{job_name}"
-    try:
-        acquired = await client.set(lock_key, token, nx=True, ex=ttl_seconds)
-        return token if acquired else None
-    finally:
-        await client.aclose()
+    acquired = await client.set(lock_key, token, nx=True, ex=ttl_seconds)
+    return token if acquired else None
 
 
 async def _release_cron_lock(job_name: str, token: str) -> None:
     """Release a previously acquired cron lock using a safe compare-and-delete."""
-    settings = get_settings()
-    client = aioredis.from_url(settings.redis_url)
+    from app.core.auth import get_redis
+
+    client = get_redis()
     lock_key = f"leocrm:cron_lock:{job_name}"
-    try:
-        # Lua script ensures we only delete if the token matches (avoid
-        # releasing a lock that was already expired and re-acquired).
-        script = (
-            b"if redis.call('get', KEYS[1]) == ARGV[1] "
-            b"then return redis.call('del', KEYS[1]) "
-            b"else return 0 end"
-        )
-        await client.eval(script, 1, lock_key, token.encode())
-    finally:
-        await client.aclose()
+    # Lua script ensures we only delete if the token matches (avoid
+    # releasing a lock that was already expired and re-acquired).
+    script = (
+        b"if redis.call('get', KEYS[1]) == ARGV[1] "
+        b"then return redis.call('del', KEYS[1]) "
+        b"else return 0 end"
+    )
+    await client.eval(script, 1, lock_key, token.encode())
 
 
 def _wrap_cron_with_lock(job_name: str, func: Any, ttl_seconds: int = 120) -> Any: