Speed up generation and ingestion; add live report progress on /status.

feat: async pipeline, job queue, generation hardening, and docs

feat: enhance embedding model configuration and retrieval logic

feat: enhance AI involvement and standard paragraph handling

- Added support for RICS survey levels (1, 2, 3) in document uploads and reports, allowing for better tier management and retrieval filtering.

- Replaced timezone.utc with UTC from datetime for consistent datetime handling.

feat: FAISS-only vector store (remove Chroma)

feat(experiment-lab): rewrite RAG pipeline using LangChain framework

fix: comprehensive codebase review fixes (critical + major + minor issues)

fix: resolve startup and background task issues for Python 3.13 + Starlette 0.52

feat: scaffold complete RAG system for RICS-style report generation