Add controller autowiring

[rtcoder]

Summary

• Create controllers through the service container instead of direct construction.
• Add ServiceContainer::make() for typed constructor dependency autowiring.
• Register the current request, router, and service container as default services by class name.
• Add tests for controller constructor autowiring and container class construction with typed dependencies.
• Update README, REFACTORING.md, and docs/index.html with the new container and controller behavior.

Validation

• composer validate --strict --no-check-publish
• composer dump-autoload
• find Engine application tests -name '*.php' -print0 | xargs -0 -n1 php -l
• composer test
• php shift.php route:list
• php shift.php health
• HTTP smoke tests:
  • GET /health -> 200 application/json
  • GET /hello -> 404 application/json

Release

• Version label: v0.10.0