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/cjs/dom/DOMRectList.d.ts

@@ -0,0 +1,21 @@
+import DOMRect from './DOMRect.cjs';
+/**
+ * DOM Rect List.
+ *
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMRectList
+ */
+export default class DOMRectList extends Array<DOMRect> {
+    /**
+     * Constructor.
+     *
+     * @param illegalConstructorSymbol Illegal constructor symbol.
+     */
+    constructor(illegalConstructorSymbol: symbol);
+    /**
+     * Returns item by index.
+     *
+     * @param index Index.
+     */
+    item(index: number): DOMRect;
+}
+//# sourceMappingURL=DOMRectList.d.ts.map