feat: hybrid RAG pipeline upgrade

fix(reranker+jina): auto-fallback to CrossEncoder + silence Jina noise

fix(3-bugs): Jina 401, reranker tokenizer, intent classifier v1 still running

fix(critical): identity leak, intent misclassification, reranker tokenizer

feat: add top stories API + fix reranker tokenizer

feat(rag): implement hybrid search with live sources and production-grade intent classification