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-canvas-element/OffscreenCanvas.d.ts

@@ -0,0 +1,47 @@
+import Blob from '../../file/Blob.js';
+import ImageBitmap from './ImageBitmap.js';
+/**
+ * OffscreenCanvas.
+ *
+ * @see https://developer.mozilla.org/en-US/docs/Web/API/OffscreenCanvas/OffscreenCanvas
+ */
+export default class OffscreenCanvas {
+    readonly width: number;
+    readonly height: number;
+    /**
+     * Constructor.
+     *
+     * @param width Width.
+     * @param height Height.
+     */
+    constructor(width: number, height: number);
+    /**
+     * Returns context.
+     *
+     * @param _contextType Context type.
+     * @param [_contextAttributes] Context attributes.
+     * @returns Context.
+     */
+    getContext(_contextType: '2d' | 'webgl' | 'webgl2' | 'webgpu' | 'bitmaprenderer', _contextAttributes?: {
+        [key: string]: any;
+    }): null;
+    /**
+     * Converts the canvas to a Blob.
+     *
+     * @param [_options] Options.
+     * @param [_options.type] Type.
+     * @param [_options.quality] Quality.
+     * @returns Blob.
+     */
+    convertToBlob(_options?: {
+        type?: string;
+        quality?: any;
+    }): Promise<Blob>;
+    /**
+     * Creates an ImageBitmap object from the most recently rendered image of the OffscreenCanvas.
+     *
+     * @returns ImageBitmap.
+     */
+    transferToImageBitmap(): ImageBitmap;
+}
+//# sourceMappingURL=OffscreenCanvas.d.ts.map