Add Beanie + Document DB Playground

[hossain-rayhan]

Summary

This PR adds a new Python Beanie playground under playgrounds/ and aligns its local run/test experience with the existing Mongoose playground.

What Changed

• Added full Beanie playground at playgrounds/beanie/:
  • README.md
  • app/ (FastAPI app, Beanie CRUD test, models, requirements)
  • scripts/ (start/stop DB, run app, run tests, shared helpers)
• Updated top-level README.md to:
  • Add Beanie to the playground table with link
  • Add Beanie quick-start commands
  • Update repository layout to include both Mongoose and Beanie
• Aligned Beanie script behavior with Mongoose:
  • run-test.sh and run-app.sh auto-start DocumentDB if needed
  • Shared helper supports container lifecycle and readiness checks
  • Default local credentials aligned for consistency across playgrounds
• Updated .gitignore to ignore Python local artifacts:
  • .venv/, __pycache__/, *.pyc
• Removed generated Python local artifacts from the copied playground.

Validation

• Beanie compatibility suite: Passed 13 / Failed 0
• Mongoose compatibility suite: Passed 16 / Failed 0 / Known issues 0
• API smoke tests passed for both playgrounds:
  • GET /health
  • POST /books
  • GET /books
  • GET /stats/genres

Notes

• DocumentDB container is not required to be pre-started anymore for Beanie run/test scripts.
• The local DB container can still be explicitly stopped via ./scripts/stop-documentdb.sh.