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/nodes/html-select-element/HTMLOptionsCollection.d.ts

@@ -0,0 +1,45 @@
+import HTMLCollection from '../element/HTMLCollection.js';
+import HTMLSelectElement from './HTMLSelectElement.js';
+import HTMLOptionElement from '../html-option-element/HTMLOptionElement.js';
+import * as PropertySymbol from '../../PropertySymbol.js';
+/**
+ * HTML Options Collection.
+ *
+ * Reference:
+ * https://developer.mozilla.org/en-US/docs/Web/API/HTMLOptionsCollection.
+ */
+export default class HTMLOptionsCollection extends HTMLCollection<HTMLOptionElement> {
+    private [PropertySymbol.ownerElement];
+    /**
+     * Constructor.
+     *
+     * @param illegalConstructorSymbol Illegal constructor symbol.
+     * @param ownerElement Select element.
+     */
+    constructor(illegalConstructorSymbol: symbol, ownerElement: HTMLSelectElement);
+    /**
+     * Returns selectedIndex.
+     *
+     * @returns SelectedIndex.
+     */
+    get selectedIndex(): number;
+    /**
+     * Sets selectedIndex.
+     *
+     * @param selectedIndex SelectedIndex.
+     */
+    set selectedIndex(selectedIndex: number);
+    /**
+     *
+     * @param element
+     * @param before
+     */
+    add(element: HTMLOptionElement, before?: number | HTMLOptionElement): void;
+    /**
+     * Removes indexed element from collection.
+     *
+     * @param index Index.
+     */
+    remove(index: number): void;
+}
+//# sourceMappingURL=HTMLOptionsCollection.d.ts.map