feat(cache): Implement unified caching subsystem with decorators, strategies, and management

- Added core caching functionality with `Cache` class supporting in-memory and file-based caching.
- Introduced `CacheManager` for high-level cache operations and statistics.
- Created various cache key generation strategies: `FilepathMethodStrategy`, `APIRequestStrategy`, `SimpleKeyStrategy`, and `CustomStrategy`.
- Developed decorators for easy method caching: `cached`, `cached_method`, `cached_api`, and `cached_property`.
- Implemented type definitions for cache entries and statistics.
- Added comprehensive tests for cache operations, strategies, and decorators to ensure functionality and backward compatibility.

renamer/cache/__init__.py

@@ -0,0 +1,107 @@
+"""Unified caching subsystem for Renamer.
+
+This module provides a flexible caching system with:
+- Multiple cache key generation strategies
+- Decorators for easy method caching
+- Cache management and statistics
+- Thread-safe operations
+- In-memory and file-based caching with TTL
+
+Usage Examples:
+    # Using decorators
+    from renamer.cache import cached, cached_api
+
+    class MyExtractor:
+        def __init__(self, file_path, cache, settings):
+            self.file_path = file_path
+            self.cache = cache
+            self.settings = settings
+
+        @cached(ttl=3600)
+        def extract_data(self):
+            # Automatically cached using FilepathMethodStrategy
+            return expensive_operation()
+
+        @cached_api("tmdb", ttl=21600)
+        def fetch_movie_data(self, movie_id):
+            # Cached API response
+            return api_call(movie_id)
+
+    # Using cache manager
+    from renamer.cache import Cache, CacheManager
+
+    cache = Cache()
+    manager = CacheManager(cache)
+
+    # Get statistics
+    stats = manager.get_stats()
+    print(f"Total cache size: {stats['total_size_mb']} MB")
+
+    # Clear all cache
+    manager.clear_all()
+
+    # Clear specific prefix
+    manager.clear_by_prefix("tmdb_")
+"""
+
+from .core import Cache
+from .managers import CacheManager
+from .strategies import (
+    CacheKeyStrategy,
+    FilepathMethodStrategy,
+    APIRequestStrategy,
+    SimpleKeyStrategy,
+    CustomStrategy
+)
+from .decorators import (
+    cached,
+    cached_method,
+    cached_api,
+    cached_property
+)
+from .types import CacheEntry, CacheStats
+
+__all__ = [
+    # Core cache
+    'Cache',
+    'CacheManager',
+
+    # Strategies
+    'CacheKeyStrategy',
+    'FilepathMethodStrategy',
+    'APIRequestStrategy',
+    'SimpleKeyStrategy',
+    'CustomStrategy',
+
+    # Decorators
+    'cached',
+    'cached_method',
+    'cached_api',
+    'cached_property',
+
+    # Types
+    'CacheEntry',
+    'CacheStats',
+
+    # Convenience functions
+    'create_cache',
+]
+
+
+def create_cache(cache_dir=None):
+    """Create a Cache instance with Manager (convenience function).
+
+    Args:
+        cache_dir: Optional cache directory path
+
+    Returns:
+        tuple: (Cache instance, CacheManager instance)
+
+    Example:
+        cache, manager = create_cache()
+        stats = manager.get_stats()
+        print(f"Cache has {stats['total_files']} files")
+    """
+    cache = Cache(cache_dir)
+    manager = CacheManager(cache)
+    return cache, manager