add ColQwen multimodal PDF retrieval integration

[ASuresh0524]

• Add ColQwenRAG class with easy-to-use CLI for multimodal PDF retrieval
• Support for both ColQwen2 and ColPali models with automatic device selection
• MPS optimization for Apple Silicon with memory-efficient loading
• Complete pipeline: PDF→images→embeddings→HNSW index→search
• Multi-vector indexing for fine-grained document matching
• Comprehensive user guide and reproduction test script
• Resolves #119: ColQwen Doc and Support Management

Features:

• python -m apps.colqwen_rag build --pdfs ./pdfs/ --index my_index
• python -m apps.colqwen_rag search my_index "query text"
• python -m apps.colqwen_rag ask my_index --interactive
• Automatic CPU fallback for memory constraints
• Robust error handling and progress tracking

Checklist

• [ ] Tests pass (uv run pytest)
• [ ] Code formatted (ruff format and ruff check)
• [ ] Pre-commit hooks pass (pre-commit run --all-files)

[yichuan-w]

The faiss submodule still seems to have some problem, we need to remember to submodule update

[yichuan-w]

@ASuresh0524

[ASuresh0524]

hmm @yichuan-w okay sounds good will look into it

[yichuan-w]

@ASuresh0524 Thanks for the PR make sure the faiss submodule is correct, and I think we create an unnecessary faiss submodule update

[ASuresh0524]

@ASuresh0524 Thanks for the PR make sure the faiss submodule is correct, and I think we create an unnecessary faiss submodule update

Sounds good, will fix this tomorrow