feat: Reinitialize frontend with SvelteKit and TypeScript

- Delete old Vite+Svelte frontend
- Initialize new SvelteKit project with TypeScript
- Configure Tailwind CSS v4 + DaisyUI
- Implement JWT authentication with auto-refresh
- Create login page with form validation (Zod)
- Add protected route guards
- Update Docker configuration for single-stage build
- Add E2E tests with Playwright (6/11 passing)
- Fix Svelte 5 reactivity with $state() runes

Known issues:
- 5 E2E tests failing (timing/async issues)
- Token refresh implementation needs debugging
- Validation error display timing

frontend/node_modules/eslint-plugin-svelte/lib/utils/cache.d.ts

@@ -0,0 +1,14 @@
+/**
+ * Simple cache manager.
+ *
+ * refer: https://github.com/mysticatea/eslint-plugin-node/blob/f45c6149be7235c0f7422d1179c25726afeecd83/lib/util/cache.js
+ */
+/**
+ * The cache will dispose of each value if the value has not been accessed
+ * during 5 seconds.
+ * @returns getter and setter ofr the cache.
+ */
+export declare function createCache<T>(): {
+    get: (key: string) => T | null;
+    set: (key: string, value: T) => void;
+};