Play Framework

Add integration test suite and CLI tests (PF-29)

Add self-contained integration tests with zero external dependencies:

Java integration tests (8 tests, forked JVM):
- Full request lifecycle: Router -> Controller -> Template -> Response
- Route parameter binding and template variable rendering
- POST with form data and echo
- Redirect (302) handling
- JSON endpoint with correct content type
- 404 for unknown routes
- Static file serving
- Play startup verification

Python CLI tests (5 tests, stdlib only):
- play version outputs version number
- play help shows command listing
- play new creates correct directory structure
- play new sets application name in config
- play new creates valid dependencies.yml

Infrastructure:
- IntegrationTestExtension bootstraps Play with fixture app
- Fixture app at test-src/integration/testapp/ with controller,
  templates, routes, and static files
- Integration tests run in forked JVM (separate from unit tests)
  to avoid Play static state conflicts
- ant test now runs: unit tests -> integration tests -> CLI tests

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>