Implement intelligent model loading for local files, URLs, and HF IDs

- Updated load_model() to handle three input types:
  1. Local files: Use directly without caching
  2. URLs: Download to cache if not cached, then use
  3. HF model IDs: Download via HF API if not cached, then use
- Updated get_cached_model_path() to validate local files
- Enhanced module documentation to reflect new capabilities
- All model types (text, image, audio, etc.) can now use any input type

codai/models/cache/__init__.py

 """
-Model Cache - Unified model caching, downloading, and management.
+Model Cache - Unified model loading, caching, downloading, and management.
 
-This module provides unified functions that work with both:
-- CoderAI GGUF cache (~/.cache/coderai/models) for downloaded GGUF files
-- HuggingFace cache (~/.cache/huggingface/hub) for HF models and datasets
+This module provides unified functions that handle three types of model sources:
+1. Local files: Used directly without caching
+2. URLs: Downloaded to CoderAI cache (~/.cache/coderai/models) if not cached
+3. HF model IDs: Downloaded to HF cache (~/.cache/huggingface/hub) if not cached
+
+All functions work seamlessly across:
+- CoderAI GGUF cache for downloaded files
+- HuggingFace cache for HF models and datasets
+- Direct local file access
 
 Functions available:
+- Intelligent model loading with automatic source detection
 - Cache directory management for all cache types
-- Checking for cached models (URLs and HF model IDs)
-- Downloading models from URLs or HuggingFace
+- Checking for cached models (URLs, HF IDs) and local file validation
+- Downloading models from URLs or HuggingFace with caching
 - Listing and removing cached models across all cache types
 """
 
@@ -59,15 +66,19 @@ def get_all_cache_dirs() -> dict:
 
 def get_cached_model_path(model_path: str) -> Optional[str]:
     """
-    Check if a model is already cached. Works with both URLs and HuggingFace model IDs.
+    Check if a model is already cached. Works with URLs, HF model IDs, and local files.
 
     Args:
-        model_path: URL or HuggingFace model ID (e.g., 'TheBloke/Llama-2-7B-GGUF')
+        model_path: Local path, URL, or HuggingFace model ID
 
     Returns:
-        Path to cached model if found, None otherwise
+        Path to cached model if found, local path if local file exists, None otherwise
     """
-    # Check if it's a HuggingFace model ID
+    # 1. Check if it's a local file - return directly if it exists
+    if os.path.isfile(model_path):
+        return model_path
+
+    # 2. Check if it's a HuggingFace model ID
     if is_huggingface_model_id(model_path):
         # For HF models, check the HF cache
         caches = get_all_cache_dirs()
@@ -91,7 +102,7 @@ def get_cached_model_path(model_path: str) -> Optional[str]:
             except (ImportError, Exception):
                 pass
     else:
-        # For URLs, check the coderai cache
+        # 3. For URLs, check the coderai cache
         cache_dir = get_model_cache_dir()
         # Create a safe filename from the URL using SHA-256 hash
         url_hash = hashlib.sha256(model_path.encode()).hexdigest()
@@ -149,24 +160,41 @@ def download_huggingface_model(model_id: str, cache_dir: Optional[str] = None, f
 
 def load_model(model_path: str, cache_dir: Optional[str] = None, file_pattern: str = '.gguf') -> Optional[str]:
     """
-    Load a model - check cache first, download if needed. Works with URLs and HF model IDs.
+    Load a model from various sources with intelligent caching.
 
-    This is the main entry point for model loading that handles caching transparently.
+    Handles three types of inputs:
+    1. Local file path: Use directly (no caching)
+    2. URL: Download if not cached, then use cached version
+    3. HF model ID: Download via HF API if not cached, then use
 
     Args:
-        model_path: URL or HuggingFace model ID (e.g., 'TheBloke/Llama-2-7B-GGUF')
+        model_path: Local path, URL, or HuggingFace model ID
         cache_dir: Specific cache directory (auto-detected if None)
         file_pattern: File pattern for HF downloads (default: '.gguf')
 
     Returns:
-        Path to cached/downloaded model, or None on failure
+        Path to model file (local or cached), or None on failure
     """
-    # First check if already cached
+    # 1. Check if it's a local file path
+    if os.path.isfile(model_path):
+        # Local file - use directly without caching
+        return model_path
+
+    # 2. Check if it's a URL (starts with http/https)
+    if model_path.startswith('http://') or model_path.startswith('https://'):
+        # URL - check cache first, download if needed
         cached_path = get_cached_model_path(model_path)
         if cached_path:
             return cached_path
+        # Not cached - download
+        return download_model(model_path, cache_dir, file_pattern)
 
-    # Not cached - need to download
+    # 3. Assume it's a HuggingFace model ID
+    # Check cache first, download if needed
+    cached_path = get_cached_model_path(model_path)
+    if cached_path:
+        return cached_path
+    # Not cached - download from HF
     return download_model(model_path, cache_dir, file_pattern)