- **Model Manager**: Central coordinator for model lifecycle, alias resolution, loading/unloading
- **Cache Module**: Handles downloading, caching, and storage of models
- **API Modules**: Request models from Model Manager (not directly from cache)

Key changes:
- Removed resolve_and_load_model() from cache - moved logic to Model Manager
- Model Manager now downloads/caches models at startup when registered
- API modules use multi_model_manager.load_model() instead of cache functions
- Proper separation: Cache=storage, Manager=lifecycle coordination, APIs=requests

This fixes the incorrect direct API-to-cache coupling and establishes proper architectural boundaries.