refactor: consolidate PHP testing actions with Laravel detection

Merge php-tests, php-laravel-phpunit, and php-composer into single php-tests action:

Consolidation:
- Merge three PHP actions into one with framework auto-detection
- Add framework input (auto/laravel/generic) with artisan file detection
- Inline PHP version detection from multiple sources
- Inline Composer setup, caching, and dependency installation
- Add conditional Laravel-specific setup steps

Features:
- Auto-detect Laravel via artisan file presence
- PHP version detection from .tool-versions, Dockerfile, composer.json, etc.
- Composer dependency management with retry logic and caching
- Laravel setup: .env copy, key generation, permissions, SQLite database
- Smart test execution: composer test for Laravel, direct PHPUnit for generic

Outputs:
- framework: Detected framework (laravel/generic)
- php-version, composer-version, cache-hit: Setup metadata
- test-status, tests-run, tests-passed: Test results

Deleted:
- php-laravel-phpunit/: Laravel-specific testing action
- php-composer/: Composer dependency management action
- Related test files and custom validators

Updated:
- CLAUDE.md: 26 → 24 actions
- generate_listing.cjs: Remove php-laravel-phpunit, php-composer
- validate-inputs: Remove php-laravel-phpunit custom validator

Result: 3 actions → 1 action, maintained all functionality with simpler interface.

validate-inputs/scripts/update-validators.py

@@ -331,9 +331,6 @@ class ValidationRuleGenerator:
                 "file-pattern": "file_pattern",
                 "plugins": "plugin_list",
             },
-            "php-laravel-phpunit": {
-                "extensions": "php_extensions",
-            },
             "codeql-analysis": {
                 "language": "codeql_language",
                 "queries": "codeql_queries",