enrichmcp 0.4.2

Changed

• Renamed app.resource decorator to app.retrieve. app.resource remains
  as a deprecated alias.

Added

• Support for marking fields as mutable with mutable=True and CRUD example
• BigInteger column type handling for SQLAlchemy integration
• Example smoke tests and improved OpenAI chat example
• Optional cleanup for SQLAlchemy lifespans
• Detailed ROBOTS guide and CI improvements