Upgrade support for PHP 8.1-8.4 and Laravel 10.x-13.x

[ConrDev]

Summary

• Broadened dependency ranges in composer.json to support Laravel 10 through 13 (>=10.0 <14.0) and the corresponding PHPUnit (>=10.5 <13.0) and Orchestra Testbench (>=8.0 <12.0) versions
• Added Dockerfiles for PHP 8.2, 8.3, and 8.4 alongside the existing 8.1 image
• Migrated test annotations from deprecated /** @test */ docblocks to #[Test] PHP attributes (required by PHPUnit 10+), including #[Depends] for dependent tests in NewsTest
• Fixed GetAppList endpoint, updated from the deprecated ISteamApps/v0001 to the current IStoreService/v1
• Fixed .env.example, removed accidental double == on STEAM_API_KEY
• Fixed GitHub Actions workflow:
  • Removed the broken Composer cache step (cache key was computed after composer update rewrote the lock file, making it ineffective)
  • Fixed invalid ${{ }} expression syntax in the coverage publish if condition and corrected github.ref to refs/heads/master
  • Fixed if: ${{ failure() }} on the Discord notification step to if: failure()

Test plan

• Run test suite against PHP 8.1, 8.2, 8.3, 8.4
• Verify tests are discovered (no more "No tests found" warnings)
• Confirm GetAppList returns results without a 404
• Check GitHub Actions runs cleanly across all matrix combinations