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/happy-dom/lib/dom-parser/DOMParser.d.ts

@@ -0,0 +1,21 @@
+import Document from '../nodes/document/Document.js';
+import * as PropertySymbol from '../PropertySymbol.js';
+import BrowserWindow from '../window/BrowserWindow.js';
+/**
+ * DOM parser.
+ *
+ * Reference:
+ * https://developer.mozilla.org/en-US/docs/Web/API/DOMParser.
+ */
+export default class DOMParser {
+    protected [PropertySymbol.window]: BrowserWindow;
+    /**
+     * Parses HTML and returns a root element.
+     *
+     * @param string HTML data.
+     * @param mimeType Mime type.
+     * @returns Root element.
+     */
+    parseFromString(string: string, mimeType: string): Document;
+}
+//# sourceMappingURL=DOMParser.d.ts.map