v0.1.0: Initial release with hybrid RAG engine

Added

• Universal RAG engine with hybrid search (vector + BM25)
• Reciprocal Rank Fusion (RRF) for combining search results
• Cross-encoder reranking for improved result quality
• Question refinement for better query expansion
• Multi-source database configuration with precedence hierarchy (CLI args → env vars → DATABASE_URL → compose file → defaults)
• RAG settings hierarchy system (query parameters → RAGConfig → database → defaults)
• Custom refinement prompt support for query expansion
• CLI commands: db-status, db-start, db-stop, db-destroy, db-restore, manifest, query
• LlamaStack integration for agent tool calling with demos
• Database utilities (check_database_status, restore_database, generate_manifest)
• Schema metadata and recent changes tracking in database
• Project URLs in package metadata (homepage, documentation, repository, issues, changelog)
• Keywords and classifiers in pyproject.toml for better PyPI discoverability

Changed

• BREAKING: UniversalRAGEngine now uses two-phase initialization pattern (constructor + await engine.start())
• BREAKING: RAGConfig fields now Optional (None = fall through to next level in hierarchy)
• db-status now displays document paths (without /source.json suffix) and shows schema metadata and recent changes
• Simplified postgres-compose.yml (removed adminer/pgadmin, standardized credentials to postgres/postgres)
• Completely rewritten README with quickstart guide, configuration hierarchy documentation, and improved structure
• Package description updated to better reflect functionality ("Query Docs2DB RAG databases with hybrid search and reranking")
• Improved type safety with assertions for Optional fields after initialization
• RAG engine now auto-detects embedding model from database if not specified
• Improved error messages for database connectivity issues and configuration conflicts

Fixed

• Fixed pytest coverage configuration to use correct package name (docs2db_api)
• Improved error handling for database configuration conflicts (DATABASE_URL + POSTGRES_* vars)