* feat(plugins): add marketplace registry routes (P2.12 M3) Add registry fetch/cache service and two public API routes for browsing and searching plugins from the remote registry at registry.barazo.forum. - src/lib/plugins/registry.ts: getRegistryIndex (fetch + Valkey cache), searchRegistryPlugins, getFeaturedPlugins - GET /api/plugins/registry/search (public, supports q/category/source) - GET /api/plugins/registry/featured (public) - 30 tests covering service logic and route behavior * fix(plugins): suppress unbound-method lint in registry tests * fix(tests): resolve lint error in plugin registry route tests Rewrite vi.mock to avoid importOriginal (consistent-type-imports rule) and fix missing closing parenthesis in mock factory.