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/browser/utilities/BrowserFrameURL.cjs

@@ -0,0 +1,29 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const url_1 = require("url");
+/**
+ * Browser frame URL utility.
+ */
+class BrowserFrameURL {
+    /**
+     * Returns relative URL.
+     *
+     * @param frame Frame.
+     * @param url URL.
+     * @returns Relative URL.
+     */
+    static getRelativeURL(frame, url) {
+        url = url ? String(url) : 'about:blank';
+        if (url.startsWith('about:') || url.startsWith('javascript:')) {
+            return new url_1.URL(url);
+        }
+        try {
+            return new url_1.URL(url, frame.window.location.href);
+        }
+        catch (e) {
+            return new url_1.URL('about:blank');
+        }
+    }
+}
+exports.default = BrowserFrameURL;
+//# sourceMappingURL=BrowserFrameURL.cjs.map