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/tests/api/test_auth_password_reset.py

@@ -188,13 +188,14 @@ class TestPasswordResetConfirm:
     @pytest.mark.asyncio
     async def test_password_reset_confirm_expired_token(self, client, async_test_user):
         """Test password reset confirmation with expired token."""
-        import time as time_module
+        import asyncio
 
-        # Create token that expires immediately
-        token = create_password_reset_token(async_test_user.email, expires_in=1)
+        # Create token that expires at current second (expires_in=0)
+        # Token expires when exp < current_time, so we need to cross a second boundary
+        token = create_password_reset_token(async_test_user.email, expires_in=0)
 
-        # Wait for token to expire
-        time_module.sleep(2)
+        # Wait for token to expire (need to cross second boundary)
+        await asyncio.sleep(1.1)
 
         response = await client.post(
             "/api/v1/auth/password-reset/confirm",