fix(guardrails): regex precision, fail-safe architecture, intent taxonomy expansion, and multi-centroid de-weighting

fix(eval): add eager startup warmup, request timeout deadline, async thread offloading, expanded safety patterns, and query intent filter

Add unignored en/hi/mr corpus, Colab GPU indexing script and notebook, and pipeline updates

fix: default cross-lingual off, concept-matrix cache, in-corpus demo prompts, UI cache styling

fix(pipeline): critical network killswitch, FAISS self-healing startup, post-retrieval confidence calibration, and semantic answer cache

feat(cross-lingual): implement cross-lingual multi-source federation RAG across Hindi, Tamil, and English with unified synthesis

feat(core): complete voice-rag-indic pipeline with STT, FAISS HNSW, BM25 rerank, guardrails, FastAPI, benchmarks, and demo