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/search.test.ts

@@ -0,0 +1,30 @@
+import { describe, expect, test } from 'bun:test';
+import type { I18nKey } from '@/lib/i18n/store';
+import { buildSettingsSearchResults } from './search';
+
+const t = (key: I18nKey): string => key;
+
+const runtimeCtx = {
+  isVSCode: false,
+  isWeb: true,
+  isDesktop: false,
+  isMobile: false,
+  isDesktopLocalOrigin: false,
+  isMac: false,
+  isWindows: false,
+  isLinux: false,
+  isWindowsArm64: false,
+};
+
+describe('settings search', () => {
+  test('finds the Claude Code third-party integration', () => {
+    const results = buildSettingsSearchResults({
+      query: 'claude',
+      runtimeCtx,
+      t,
+      getPageTitle: (page) => page,
+    });
+
+    expect(results.some((result) => result.id === 'integrations.third-party.opencode-claude')).toBe(true);
+  });
+});