CRITICAL FIX for beginners: User config model changes now work correctly
Issues Fixed:
- rag-mini.py synthesis mode ignored config completely (used hardcoded models)
- LLMSynthesizer fallback ignored config preferences
- Users changing model in config saw no effect in synthesis mode
Changes:
- rag-mini.py now loads config and passes synthesis_model to LLMSynthesizer
- LLMSynthesizer _select_best_model() respects config model_rankings for fallback
- All modes (synthesis and explore) now properly use config settings
Tested: Model config changes now work correctly in both synthesis and explore modes