Simple RAG for Symfony DOCS

Hybrid search with `nomic-ai/CodeRankEmbed` embeddings over summaries for tree nodes + BM25 search over node texts with RRF. Reranker `onnx-community/bge-reranker-base-ONNX` with int8 quantization. Answer generation done with Z.AI GLM-4-32B-0414-128K