Play Framework

fix(testrunner): serve Tailwind CSS from module-namespaced path (PF-91)

The testrunner's @tests page was rendering with broken styling
because its index.html linked to /public/stylesheets/play-tailwind.css,
which Play 1's static-dir resolver serves from the *app's* public/
directory. Apps scaffolded before the Tailwind migration (commit
188be7164, 2026-04-06) carry pre-Tailwind CSS with high-specificity
ID selectors (e.g. `#header { background:#67A927 }`) that override
the new utility classes — the page renders with the old palette and
no flexbox/spacing utilities applied.

Move the testrunner's CSS to /public/test-runner/play-tailwind.css,
matching the namespacing already used for running.gif. This path is
served from the testrunner module's public/ via Play's module asset
resolver and is not shadowed by the app's own public/stylesheets/.

Changes:
- testrunner index.html: stylesheet href moved to test-runner/
- build-css.sh: emit testrunner CSS at modules/testrunner/public/
  test-runner/play-tailwind.css (new file, alongside running.gif)
- regenerated all three CSS outputs (skel, docviewer, testrunner)
  with the framework's local tailwindcss v4.2.4 binary

Note: docviewer keeps the /public/stylesheets/ path because its
pages are served by the framework's own routes, not from inside
end-user apps.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>