fix: format professional theme stylesheet

[btcneves]

Summary

• Formats frontend/src/professional-theme.css with Prettier.
• Restores the frontend CI Format check that failed on main.

Validation

• npm run format:check passed.
• npm run lint passed.
• npm run typecheck passed.
• npx vite build --outDir /tmp/nodescope-ci-fix-dist --emptyOutDir passed.
• docker compose config passed.
• make public-clean passed.
• git diff --check passed.

Notes

• Local npm run build hit an existing frontend/dist permission issue from ignored local artifacts, so the same Vite build was validated with a temporary output directory.
• Backend CI was already passing on the failing main run.