Hotbar 0.2.4

• Fixed: 0.2.3 did not load. Quickshell 0.3.1's Process has no
  errorOccurred signal, so the two onErrorOccurred handlers added for
  the warp helpers made the whole widget fail with "Cannot assign to
  non-existent property" (the installed 0.2.2 kept working, which hid it).
  Helper failures are now caught by one-shot watchdog timers that clear
  the busy state and report unknown / the inline apply error;
  tests/test_warp_ui.js rejects the handler from now on.
• Greyforge Labs identity throughout: the Places cell is the steel hexagon
  mark holding the three pin slots (amber core on the middle pin, cyan seams
  on hover and while a popover is open); every popover opens with the mark,
  a "HOTBAR · GREYFORGE LABS" eyebrow, the title, an amber count chip, and
  a steel rule, and closes with the Greyforge Labs wordmark. The app menu
  shows the app's own icon inside the mark. Settings shows the version in
  its eyebrow and hotbar doctor in its footer. Empty drawers show the
  mark instead of bare text. Brand components live in brand/.
• Cells press in briefly on click.
• CI: the doctor warp test no longer fails on hosts without uwsm-app /
  gtk-launch / the plugin dir (it asserts the warp lines, not the exit code).
• Screenshots in docs/screenshots/.