fix(ci): resolve uat lint + typecheck failures (CAR-1340)

- cache.py:38: Add explicit type annotation for redis.get() return value to resolve mypy no-any-return
- rate_limit.py: Remove duplicate forward-declaration block (dead code, mypy no-redef)
- conftest.py: Remove one excess blank line to satisfy ruff format check

All three fixes verified locally: ruff check ✅, ruff format ✅, mypy ✅

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/cartsnitch_api/cache.py

@@ -35,7 +35,7 @@ class CacheClient:
     async def get(self, key: str) -> str | None:
         if not self._client:
             return None
-        value = await self._client.get(key)
+        value: str | bytes | None = await self._client.get(key)
         if value is None:
             return None
         if isinstance(value, bytes):

src/cartsnitch_api/middleware/rate_limit.py

@@ -121,10 +121,6 @@ if settings.rate_limit_redis_enabled:
         logger.warning("Failed to connect to Redis for rate limiting, using in-memory: %s", e)
         _use_redis = False
 
-_public_limiter: RateLimitBackend
-_auth_limiter: RateLimitBackend
-_auth_strict_limiter: RateLimitBackend
-
 if _use_redis and _redis_client:
     _public_limiter = RedisSlidingWindow(
         _redis_client, settings.rate_limit_requests, settings.rate_limit_window_seconds

tests/conftest.py

@@ -117,7 +117,6 @@ def _register_event_listeners():
             event.listen(cls, "before_insert", _set_timestamp_defaults)
 
 
-
 TEST_JWT_SECRET = secrets.token_urlsafe(32)
 TEST_SERVICE_KEY = secrets.token_urlsafe(32)
 TEST_FERNET_KEY = "7reF42nmTwbdN21PBoubGp7h_FU8qSimstmlaMLoRK8="