🐛 fix: restore localized blog routes and runnable CI

[zrr1999]

Summary

• Restore Chinese search by sharing a bundled search component across both locales. Recreate Pagefind when navigating between languages, and keep the URL and return link in sync when clearing a query.
• Use the existing locale helpers for English article, tag, archive, RSS and image routes. Keep empty article listings available and exclude unpublished translations from language links.
• Place the 16 unchanged Chinese drafts under the existing zh/ content convention. Fix tag pagination's static-path scope so publishing articles does not break the build.
• Restore CI installation by using the maintained, commit-pinned ZenDev title action and an available rumdl release. The previous action repository is gone and PyPI no longer provides the pinned rumdl 0.1.63 package.

Validation

• pnpm install --frozen-lockfile, pnpm run ci, prek run --all-files, and the installed pre-commit and commit-message hooks passed.
• Reproduced the original production error in Chromium: Chinese search had no input and raised Cannot use 'import.meta' outside a module.
• The fixed production build passed 12 browser checks covering both locales, real indexed results, clearing by button and keyboard, query preservation, locale switching, and back/forward navigation, with no page exceptions.
• A separate build with temporary English/Chinese articles passed 23 checks covering pagination, tags, RSS, locale isolation, published translation links, and exclusion of drafts and future posts. Fixtures were removed before the final production build and are not included in this PR.

Notes

Stack base: main. Follow-up shared-validation migration: #15. Site and static checks now also run for PRs targeting another stack branch.

The drafts remain unpublished and their contents are unchanged. The CI repair preserves every existing check and its configuration rules.