Chat App Frontend and Backend

[bharatr21]

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Note

Builds a full RAG chat backend with robust APIs, retrieval, and testing, plus CI and developer tooling.

• Implements FastAPI app with api/chat, api/documents, api/sessions, api/models, health, CORS, and Pydantic schemas
• Adds RAG stack: HybridRetriever (HNSW + BM25 with RRF), RAGPipeline, LLMProvider (OpenAI/Anthropic/Google/HuggingFace), Vercel-compatible streaming
• Introduces secure file/session storage, metadata management, filename sanitization, and path traversal protections
• Provides config via .env.example and app/config.py (BYOK keys, ChromaDB, session store, limits)
• Adds comprehensive tests (API, services, retriever, pipeline, config) and summaries; sets up pyproject.toml
• Establishes CI workflow (.github/workflows/ci.yml), pre-commit hooks, updated README.md, and .gitignore entries

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Summary by CodeRabbit

• New Features

  • RAG chat with streaming & non‑streaming replies, session management, multi‑provider model selection, and in‑app API key management modal.

• Frontend

  • Full chat UI, drag‑and‑drop document upload with validation, document selector, model selector, hooks, API client, and reusable UI components.

• Backend

  • Document CRUD, RAG pipeline & hybrid retriever, chat API with sessions, model discovery, centralized configuration and env examples, file-backed session storage.

• Documentation

  • Expanded README, environment examples, CI docs, and test coverage summary.

• Tests

  • Extensive unit, integration, and end‑to‑end suites added.

• Chores

  • Docker Compose, CI workflow, linters, pre‑commit, and gitignore updates.

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