prefer Playwright chromium over sys Chrome by default

[laithrw]

Resolves #4610

Summary by cubic

Prefer the playwright-bundled Chromium over system Chrome by default to make local launches consistent across machines and CI. Also switches installation to uvx playwright install chromium.

• Refactors
  • Reordered search priority: channel-specific (non-default) -> Playwright Chromium -> system Chrome -> other native browsers -> Playwright headless-shell.
  • Unified pattern ordering to always prioritize the target browser group, then fall back to others.
  • Switched install command and error messages from chrome to chromium.

^{Written for commit 03e2bc4. Summary will update on new commits.}

[github-actions]

Agent Task Evaluation Results: 2/2 (100%)

View detailed results

Task	Result	Reason
amazon_laptop	✅ Pass	Skipped - API key not available (fork PR or missing secret)
browser_use_pip	✅ Pass	Skipped - API key not available (fork PR or missing secret)

Check the evaluate-tasks job for detailed task execution logs.

[cubic-dev-ai]

No issues found across 1 file