Ctrl+F is a common search shortcut and should open the launcher search just
like the existing slash shortcut. Handle it in the same SearchField keydown
listener so the behavior stays scoped to the topbar search component.
The shortcut is ignored while the user is already typing in another input or
textarea, matching the existing slash behavior. When handled, it prevents the
webview's browser find UI and focuses the app search field instead.
Test Plan:
- `just frontend-test`
Refs: none
ddidderr
debb1c0c49
