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/event/UIEvent.js

@@ -0,0 +1,28 @@
+import Event from './Event.js';
+/**
+ *
+ */
+export default class UIEvent extends Event {
+    static NONE = 0;
+    static CAPTURING_PHASE = 1;
+    static AT_TARGET = 2;
+    static BUBBLING_PHASE = 3;
+    detail;
+    layerX = 0;
+    layerY = 0;
+    pageX = 0;
+    pageY = 0;
+    view;
+    /**
+     * Constructor.
+     *
+     * @param type Event type.
+     * @param [eventInit] Event init.
+     */
+    constructor(type, eventInit = null) {
+        super(type, eventInit);
+        this.detail = eventInit?.detail ?? 0;
+        this.view = eventInit?.view ?? null;
+    }
+}
+//# sourceMappingURL=UIEvent.js.map