Retrieval fixes: robust nprobe tuning + goals-only query

Swap MiniLM retriever for LeanDojo's ByT5 premise encoder

Pin ruff to 0.15.14 and re-sort imports

Add CI/CD: GitHub Actions workflow + ruff config

Merge pull request #8 from ray5th/worktree-agent-a0c1e62025fb04462

Gracefully skip RAG when FAISS index is missing

Fuzz retriever query handling (fix missing input guards)

Fix LLM hallucinated imports and slow thinking mode (#2)

Add LangChain/LangGraph RAG pipeline for retrieval-augmented proof generation

rework

Initial commit: Agentic Lean 4 Theorem Prover