feat(settings): add third-party integrations dashboard

Add a Settings → Integrations page for installing and managing the three
supported OpenCode provider plugins (Claude Code, Command Code, Cursor),
with search, i18n, and plugin-registry status wiring.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/ui/src/apps/MobileApp.tsx

@@ -83,6 +83,7 @@ const MOBILE_SETTINGS_PAGES = [
   'providers',
   'usage',
   'voice',
+  'integrations',
   'about',
 ] as const;