Release v0.5.0

+## What’s New (Today’s Commit)
+* 🚚 Removed the old rust-bert embedding backend and fully replaced it with TEI (Text Embeddings Inference v1.7.0).
+* 🔧 Updated all embedding code paths (Ollama, TEI, Google) to work seamlessly with the new TEI client.
+* 📝 Improved logging (via env_logger) so RUST_LOG=debug now shows all internal db2vec events.
+* 📦 Bundled the TEI binaries (tei-metal / tei-onnx) and added automatic extraction if no --tei-binary-path is provided.