wp/6.5 branch: Restore automated testing capabilities and GitHub Actions workflows #82928

Summary

This applies the changes necessary to ensure the GitHub Actions and automated tooling in the wp/6.5 branch are in a working and maintainable state going forward.

PR stack (bottom to top)

1. Remove obsolete and trunk-only workflows (Repair wp/6.5 branch Actions: Remove obsolete and trunk-only workflows #82988)
2. Add timeouts to CI jobs that have none (Repair wp/6.5 branch Actions: Add timeouts to CI jobs that have none #84477)
3. Disable npm caching in release workflows (Repair wp/6.5 branch Actions: Disable npm caching in release workflows #83406)
4. Update GitHub Actions to their latest versions (Repair wp/6.5 branch Actions: Update GitHub Actions to their latest versions #82990)
5. Remove svn --version debug check (Repair wp/6.5 branch Actions: Remove svn --version debug check #83001)
6. Refine push branch filters (Repair wp/6.5 branch Actions: Refine push branch filters #82999)
7. Remove the broken flaky-test issue reporting job (Repair wp/6.5 branch Actions: Remove the broken flaky-test issue reporting job #82996)
8. Remove the mobile-unit-js job (Repair wp/6.5 branch Actions: Remove the mobile-unit-js job #83297)
9. Test against a single Node.js version (Repair wp/6.5 branch Actions: Test against a single Node.js version #82991)
10. Pin runner images instead of *-latest (Repair wp/6.5 branch Actions: Pin runner images instead of *-latest #82998)
11. Remove docker-compose -v debug check (Repair wp/6.5 branch Actions: Remove docker-compose -v debug check #83003)
12. Fix wp-env Docker builds broken by archived Debian Buster/Bullseye repositories and expired Debian Stretch signing keys (Repair wp/6.5 branch Actions: Fix wp-env Docker builds broken by archived Debian Buster/Bullseye repositories and expired Debian Stretch signing keys #82995)
13. Pin wp-env to the correct WordPress Core version (Repair wp/6.5 branch Actions: Pin wp-env to the correct WordPress Core version #82992)
14. Fix the Composer PHP platform override breaking unit tests on older PHP (Repair wp/6.5 branch Actions: Fix the Composer PHP platform override breaking unit tests on older PHP #82994)
15. Update the PHP version test matrix (Repair wp/6.5 branch Actions: Update the PHP version test matrix #83000)
16. Ignore the stale Browserslist data warning in unit tests (Repair wp/6.5 branch Actions: Ignore the stale Browserslist data warning in unit tests #82993)
17. Upgrade Playwright to fix Ubuntu 24.04 (Noble) browser-install failures (Repair wp/6.5 branch Actions: Upgrade Playwright to fix Ubuntu 24.04 (Noble) browser-install failures #82997)
18. Fix theme-activation navigation race in activate-theme.js (Repair wp/6.5 branch Actions: Fix theme-activation navigation race in activate-theme.js #83002)
19. Fix flaky Openverse image drag-and-drop e2e test (Repair wp/6.5 branch Actions: Fix flaky Openverse image drag-and-drop e2e test #83621)
20. Fix flaky block switcher max-columns e2e test (Repair wp/6.5 branch Actions: Fix flaky block switcher max-columns e2e test #83622)
21. Fix flaky block switcher columns-range e2e test (Repair wp/6.5 branch Actions: Fix flaky block switcher columns-range e2e test #83623)
22. Improve reliability of TinyMCE-related tests (Repair wp/6.5 branch Actions: Improve reliability of TinyMCE-related tests #83466)
23. Fix flaky interactivity router navigate e2e test (Repair wp/6.5 branch Actions: Fix flaky interactivity router navigate e2e test #83657)
24. Reset preferences after navigable toolbar e2e tests (Repair wp/6.5 branch Actions: Reset preferences after navigable toolbar e2e tests #83726)
25. Fix flaky site editor URL navigation e2e test (Repair wp/6.5 branch Actions: Fix flaky site editor URL navigation e2e test #83728)
26. Pass debug step arguments through to wp-env (Repair wp/6.5 branch Actions: Pass debug step arguments through to wp-env #83804)
27. Detect the database client in the debug step (Repair wp/6.5 branch Actions: Detect the database client in the debug step #83837)
28. Add a mariadbVersion option to wp-env (Repair wp/6.5 branch Actions: Add a mariadbVersion option to wp-env #83816)
29. Replace wp-env's database check with a MariaDB health check (Repair wp/6.5 branch Actions: Replace wp-env's database check with a MariaDB health check #83866)
30. Pin MariaDB to 10.11 (Repair wp/6.5 branch Actions: Pin MariaDB to 10.11 #83825)
31. Fix flaky Tabs unit test (Repair wp/6.5 branch Actions: Fix flaky Tabs unit test #84588)
32. Set explicit retention periods for workflow artifacts (Repair wp/6.5 branch Actions: Set explicit retention periods for workflow artifacts #84749)
33. Remove the unused flaky test report uploads and reporter (Repair wp/6.5 branch Actions: Remove the unused flaky test report uploads and reporter #85109)
34. Run macOS and Windows jobs only on WordPress/gutenberg (Repair wp/6.5 branch Actions: Run macOS and Windows jobs only on WordPress/gutenberg #85133)
35. Upload each E2E job's debug artifacts under its own name (Repair wp/6.5 branch Actions: Upload each E2E job's debug artifacts under its own name #85328)
36. Pin the PHP version used by the end-to-end tests (Repair wp/6.5 branch Actions: Pin the PHP version used by the end-to-end tests #85337)
37. Fix flaky Composite and Tabs unit tests (Repair wp/6.5 branch Actions: Fix flaky Composite and Tabs unit tests #85478)
38. Fix flaky component unit tests that press Tab (Repair wp/6.5 branch Actions: Fix flaky component unit tests that press Tab #85682)
39. Fix flaky deferred store e2e test (Repair wp/6.5 branch Actions: Fix flaky deferred store e2e test #85683)

Follow-up PRs

• Raise the Node.js heap limit for CI build steps (Build: Raise the Node.js heap limit for CI build steps (wp/6.5) #85691)
• Pin the site title in the Interactivity API router specs (E2E: Pin the site title in the Interactivity API router specs (wp/6.5) #85699)

Note: all PRs that are not marked as "ready for review" should be considered unreviewed by a human.