[codex] PR_26175_ALFA_005 game hub audit findings cleanup

[ToolboxAid]

Summary

• Replaced the active BUILD_PR.md with PR_26175_ALFA_005 as the source of truth.
• Cleaned up the four targeted ALFA_004 Game Hub audit findings in GameHubMockRepository.spec.mjs.
• Scoped the deprecated-route link lookup to main, narrowed stale Game Status checks to legacy form controls, and added an explicit Playwright fixture for the toolbox index completion-metrics request.
• Added ALFA_005 report, validation lane, requirements checklist, changed-files report, review diff, and repo-structured delta ZIP metadata.

Validation

• PASS: npx playwright test tests/playwright/tools/GameHubMockRepository.spec.mjs --workers=1 ran 14 tests: 14 passed, 0 failed.
• PASS: changed-source style scan found no inline style or style-block matches.
• PASS: git diff --cached --check before commit.

Notes

• No Game Hub product/UI files changed.
• No Game Journey API/service/persistence files changed.
• Delta ZIP: tmp/PR_26175_ALFA_005-game-hub-audit-findings-cleanup_delta.zip.
• Commit: 0167f1abae8d1a3f60433f525081100d9740588a.