feat: add environment variables for reranking and timeout settings; enhance logging for retrieval and generation durations

feat: add prewarm functionality for retrieval resources during API startup

feat: implement bibliographic citation handling with source metadata integration

feat: Implement RAG pipeline progress visualization and enhance code block copy button feedback.

Change default LLM provider from Gemini to Groq

feat: Multiple UI and backend improvements

Handle legacy manifest format gracefully

Fix: use dict type annotation with manual validation to avoid forward reference issues

Fix: add model_rebuild() to resolve Pydantic forward references

Fix: remove /api prefix from routes - nginx already strips it

Prepare for HF Space deployment

Initial commit for HF Space