fix(mem0_oss): fix misrouted last-attempt lock error in _get_memory

The else branch for non-lock errors was incorrectly triggered on the
final retry attempt of a Qdrant lock error, causing it to log ERROR
and raise immediately rather than fall through to the lock-exhausted
path. This tripped the circuit breaker during startup when WebUI and
gateway processes competed for the lock.

Fix: add a comment to skip the else on last lock-error attempt, and
downgrade the exhausted-retries log from ERROR to WARNING since lock
contention is expected and not a hard failure.

plugins/memory/mem0_oss/__init__.py

@@ -629,11 +629,15 @@ class Mem0OSSMemoryProvider(MemoryProvider):
                         )
                         _time.sleep(delay)
                         continue
+                    # Last attempt also a lock error — fall through to raise below
                 else:
                     # Non-lock error — fail fast, no retry
                     logger.error("mem0_oss: failed to initialize Memory: %s", exc)
                     raise
-        logger.error("mem0_oss: failed to initialize Memory after %d attempts: %s", _LOCK_RETRY_ATTEMPTS, last_exc)
+        logger.warning(
+            "mem0_oss: Qdrant lock still held after %d attempts — giving up: %s",
+            _LOCK_RETRY_ATTEMPTS, last_exc,
+        )
         raise last_exc  # type: ignore[misc]
 
     # -- Circuit breaker helpers -------------------------------------------