0.2.0

fix(ci): bake the tag version into tagged desktop builds

publish.yml packaged whatever static version sat in
release/app/package.json (0.1.0) regardless of the tag — a v0.2.0 tag
would ship an app reporting 0.1.0, older than every installed nightly,
so no updater would ever take it. Mirror the nightly bump step but with
the tag as the single source of truth (v0.2.0 → app 0.2.0), validated
as vX.Y.Z. Build-time only, never committed.