ci: narrow files-changed frontend filter (#37749)

Drop the broad `tools/*.{js,ts}` globs from the `frontend` filter so
edits to CI-only or backend helper scripts in `tools/` stop triggering
frontend and e2e jobs. Only `tools/generate-svg.ts` is kept.

Also renames `tools/lint-pr-title.js` to `.ts` for consistency, drops
the empty root `*.js` glob, fixes stray indentation in the `dockerfile`
filter and adds missing `setup-node`.

---
This PR was written with the help of Claude Opus 4.7

---------

Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>

.github/workflows/pull-pr-title.yml

@@ -23,6 +23,9 @@ jobs:
     timeout-minutes: 5
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
+        with:
+          node-version: 24
       - run: make lint-pr-title
         env:
           PR_TITLE: ${{ github.event.pull_request.title }}