refactor: consolidate to PostgreSQL-only backend and modernize stack
Remove legacy storage implementations and deprecated examples:
- Delete FAISS, JSON, Memgraph, Milvus, MongoDB, Nano Vector DB, Neo4j, NetworkX, Qdrant, Redis storage backends
- Remove Kubernetes deployment manifests and installation scripts
- Delete unofficial examples for deprecated backends and offline deployment docs
Streamline core infrastructure:
- Consolidate storage layer to PostgreSQL-only implementation
- Add full-text search caching with FTS cache module
- Implement metrics collection and monitoring pipeline
- Add explain and metrics API routes
Modernize frontend and tooling:
- Switch web UI to Bun with bun.lock, remove npm and pnpm lockfiles
- Update Dockerfile for PostgreSQL-only deployment
- Add Makefile for common development tasks
- Update environment and configuration examples
Enhance evaluation and testing capabilities:
- Add prompt optimization with DSPy and auto-tuning
- Implement ground truth regeneration and variant testing
- Add prompt debugging and response comparison utilities
- Expand test coverage with new integration scenarios
Simplify dependencies and configuration:
- Remove offline-specific requirement files
- Update pyproject.toml with streamlined dependencies
- Add Python version pinning with .python-version
- Create project guidelines in CLAUDE.md and AGENTS.md