fix(tests): reduce TTL durations to improve test reliability

- Adjusted TTL durations and sleep intervals across memory and cache tests for consistent expiration behavior.
- Prevented test flakiness caused by timing discrepancies in token expiration and cache cleanup.

backend/app/models/memory/fact.py

@@ -18,7 +18,10 @@ from sqlalchemy import (
     Text,
     text,
 )
-from sqlalchemy.dialects.postgresql import JSONB, UUID as PGUUID
+from sqlalchemy.dialects.postgresql import (
+    JSONB,
+    UUID as PGUUID,
+)
 from sqlalchemy.orm import relationship
 
 from app.models.base import Base, TimestampMixin, UUIDMixin