- Move model_parser.py into codai/ directory
- Add __init__.py to make it a proper Python module
- Create ModelParserAdapter class to wrap ModelParserDispatcher
- Replace ToolCallParser() with ModelParserAdapter() in 4 locations
- Update import to use 'from codai import ModelParserDispatcher'

This enables model-specific tool call parsing for Qwen, DeepSeek,
Llama, Mistral, Claude, Command R, Gemma, Grok, and Phi models.