feat(frontend): setup frontend foundation

- Install dependencies: date-fns, @vite-pwa/sveltekit, workbox-window
- Configure Vite with PWA support and manifest
- Update SvelteKit config for static adapter with fallback
- Create environment files (.env, .env.example, .env.production)
- Create directory structure for lib, components, routes
- Add JSDoc type definitions for Task, User, AuthTokens, etc.
- Add utility functions: storage (localStorage wrapper), uuid, dates, sync-queue
- Configure PWA with icons, theme colors, and caching strategies

opal-web/package.json

@@ -15,9 +15,14 @@
 		"@sveltejs/adapter-static": "^3.0.10",
 		"@sveltejs/kit": "^2.49.1",
 		"@sveltejs/vite-plugin-svelte": "^6.2.1",
+		"@vite-pwa/sveltekit": "^1.1.0",
 		"svelte": "^5.45.6",
 		"svelte-check": "^4.3.4",
 		"typescript": "^5.9.3",
-		"vite": "^7.2.6"
+		"vite": "^7.2.6",
+		"workbox-window": "^7.4.0"
+	},
+	"dependencies": {
+		"date-fns": "^4.1.0"
 	}
 }