The client version shown on the Settings page was hardcoded as a
literal in vite.config.ts, while client/package.json sat at the
placeholder "0.0.0". Bumping the displayed version required editing
two unrelated places, and stale Docker client images would keep
showing the old number after upgrades.
This change makes client/package.json the single source of truth
and reads it at build time. Bumps client/package.json from 0.0.0
to 3.6.1 to preserve current behaviour.
Closes#3271