Fix duplicate caching (#62)

* Fix duplicate/redundant caching issue

- Add get_background_cached_data() and is_background_data_available() methods to CacheManager
- Update sports managers to use background service cache instead of individual caching
- Ensure consistent cache key generation between background service and managers
- Eliminate redundant API calls by making Recent/Upcoming managers cache consumers
- Fix cache miss issues where TTL < update interval

This addresses GitHub issue #57 by implementing a cleaner caching architecture
where the background service is the primary data source and managers are cache consumers.

* Update remaining sports managers to use background service cache

- Update NHL managers to use background service cache
- Update NCAA Football managers to use background service cache
- Update NCAA Hockey managers to use background service cache
- Update MLB managers to use background service cache for Recent/Upcoming

All sports managers now use the new caching architecture to eliminate
duplicate caching and redundant API calls.

* cache improvements

* updated cache manager

src/background_data_service.py

@@ -128,11 +128,22 @@ class BackgroundDataService:
         
         logger.info(f"BackgroundDataService initialized with {max_workers} workers")
     
+    def get_sport_cache_key(self, sport: str, date_str: str = None) -> str:
+        """
+        Generate consistent cache keys for sports data.
+        This ensures Recent/Upcoming managers and background service
+        use the same cache keys.
+        """
+        # Use the centralized cache key generation from CacheManager
+        from src.cache_manager import CacheManager
+        cache_manager = CacheManager()
+        return cache_manager.generate_sport_cache_key(sport, date_str)
+
     def submit_fetch_request(self, 
                            sport: str, 
                            year: int, 
                            url: str,
-                           cache_key: str,
+                           cache_key: str = None,
                            params: Optional[Dict[str, Any]] = None,
                            headers: Optional[Dict[str, str]] = None,
                            timeout: Optional[int] = None,
@@ -160,6 +171,10 @@ class BackgroundDataService:
         if self._shutdown:
             raise RuntimeError("BackgroundDataService is shutting down")
         
+        # Generate cache key if not provided
+        if cache_key is None:
+            cache_key = self.get_sport_cache_key(sport)
+        
         request_id = f"{sport}_{year}_{int(time.time() * 1000)}"
         
         # Check cache first