chore: apply oxlint fix-suggestions (unused imports + useless fragments)

Scoped to only `no-unused-vars` and `react/jsx-no-useless-fragment` —
the safe subset of --fix-suggestions. Primary changes:

- Remove unused named imports from statements
- Remove unused default/type imports entirely
- Collapse `<><Single/></>` fragments to `<Single/>`

Verified clean: typecheck + format + lint all green.

packages/app/src/desktop/permissions/use-desktop-permissions.ts

@@ -132,7 +132,7 @@ export function useDesktopPermissions(): UseDesktopPermissionsReturn {
           "Notification was not delivered. Check System Settings > Notifications.",
         );
       }
-    } catch (error) {
+    } catch {
       setTestNotificationError("Failed to send notification.");
     } finally {
       if (isMountedRef.current) {