feat(frontend): add Vue 3 web application

- Add Vue 3 + TypeScript + Pinia setup
- Add 6 complete views: Dashboard, Queue, Scanner, Rules, Workers, Settings
- Add Pinia stores for state management
- Add API service with Axios client
- Add dark theme with Tdarr-inspired styling
- Add setup wizard component
- Add path browser for filesystem navigation

frontend/env.d.ts

@@ -0,0 +1,8 @@
+/// <reference types="vite/client" />
+
+declare module '*.vue' {
+  import type { DefineComponent } from 'vue'
+  const component: DefineComponent<{}, {}, any>
+  export default component
+}
+