fix(embedding): update fastembed to 5.0.2 and ensure thread safety

- Bump fastembed and core dependencies to latest versions
- Wrap FastEmbed model in Mutex for safe concurrency
- Update embedding dimension retrieval to use blocking thread
- Align code with updated fastembed API and concurrency needs
- Upgrade DataFusion, ort, hf-hub, ureq, and related crates
- Remove explicit version pins and deprecated dependencies
- Add new dependencies and clean up Cargo.lock for consistency

Author: donhardman