feat(settings): add item search (#1592)

Adds item-level search inside Settings so users can find concrete settings like provider auth, agent mode, terminal font size, tunnel options, notification events, and similar controls instead of only filtering top-level pages.
Groups search results by Settings page and shows localized labels plus optional descriptions where useful.
Supports keyboard navigation with Arrow Up/Down, Enter, and Escape, matching the existing autocomplete interaction style.
Opens the correct Settings page or split-page draft state before scrolling to the matching control.
Highlights the matched setting with a subtle token-based background so users can see where they landed without an aggressive outline.
Adds explicit data-settings-item anchors across Settings pages and a centralized search registry with runtime/mobile availability guards.
Updates Settings UI skill guidance so future Settings changes keep search registry entries, anchors, localization, and availability guards in sync.

packages/ui/src/lib/i18n/messages/es.settings.ts

@@ -28,6 +28,10 @@ export const settingsDict = {
   "settings.view.actions.closeSettingsWithShortcut": "Cerrar configuración ({shortcut}+,)",
   "settings.view.actions.back": "Atrás",
   "settings.view.actions.resizeNavigation": "Ajustar tamaño de la navegación",
+  "settings.view.search.placeholder": "Buscar configuración",
+  "settings.view.search.aria": "Buscar configuración",
+  "settings.view.search.clear": "Borrar búsqueda de configuración",
+  "settings.view.search.noResults": "No hay configuraciones coincidentes",
   "settings.page.projects.title": "Proyectos",
   "settings.page.remoteInstances.title": "Instancias remotas",
   "settings.page.providers.title": "Proveedores",