style(web): format locale regression test

[Tutitoos]

Related issue

Closes #196

Plan reference

Operational Phase 3 CI correction following the locale rerender fix.

Summary

Apply the repository Biome formatting required by CI to the new locale regression test.

Changes

• Format the Playwright test callback using the canonical Biome layout.

Validation

• Relevant automated checks pass

• Manual verification completed where needed

• bun run lint — passed, 81 files checked.

• Behavioral validation remains unchanged from fix(web): rerender installed locale catalogs #197: 50 unit tests and 24 bootstrap browser tests passed.

Risks and rollback

Formatting-only change; no runtime behavior changes. Revert this PR to roll back.

Checklist

• The PR has one coherent scope
• The branch and Closes reference identify the same primary issue
• The issue acceptance criteria are satisfied
• No secrets, credentials, personal data, or unintended files are included
• Documentation and tests are updated when applicable
• Breaking changes are explicitly documented (none)