feat: Enhance LLM resilience with a multi-provider fallback system, upgrade the default Ollama model to 7B, and improve vector store relevance score calculation.
feat: Implement multi-file upload for DOCX, TXT, and MD documents, improve SQL table cleanup with name validation and quoting, and update file uploader UI.
feat: Refactor PDF processing to use pymupdf4llm for markdown extraction and MarkdownTextSplitter for intelligent chunking, adding necessary dependencies.