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/lib/settings/metadata.ts

@@ -25,7 +25,8 @@ export type SettingsPageSlug =
   | 'notifications'
   | 'voice'
   | 'tunnel'
-  | 'about';
+  | 'about'
+  | 'integrations';
 
 type SettingsPageGroup =
   | 'general'
@@ -201,6 +202,7 @@ export const SETTINGS_PAGE_METADATA: readonly SettingsPageMeta[] = [
   { slug: 'voice', title: 'Voice', group: 'general', kind: 'single', keywords: ['tts', 'speech', 'voice'], isAvailable: (ctx) => !ctx.isVSCode },
   { slug: 'tunnel', title: 'External Tunnel', group: 'projects', kind: 'single', keywords: ['tunnel', 'external', 'cloudflare', 'qr', 'remote', 'mobile', 'share'], isAvailable: (ctx) => !ctx.isVSCode },
   { slug: 'about', title: 'About', group: 'general', kind: 'single', keywords: ['about', 'version', 'updates', 'release', 'changelog'], isAvailable: (ctx) => ctx.isMobile && !ctx.isVSCode },
+  { slug: 'integrations', title: 'Integrations', group: 'general', kind: 'single', keywords: ['integration', 'plugin', 'provider', 'oauth', 'claude', 'cursor', 'command code', 'connect'] },
 ] as const;
 
 const LEGACY_SIDEBAR_SECTION_TO_SETTINGS_SLUG: Record<SidebarSection, SettingsPageSlug> = {
@@ -286,6 +288,9 @@ export function getSettingsNavIcon(slug: SettingsPageSlug): IconName | null {
     case 'git':
       return 'git-branch';
 
+    case 'integrations':
+      return 'plug';
+
     case 'usage':
       return 'bar-chart-2';
     case 'voice':