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-base-element/HTMLBaseElement.js

@@ -0,0 +1,58 @@
+import HTMLElement from '../html-element/HTMLElement.js';
+import * as PropertySymbol from '../../PropertySymbol.js';
+/**
+ * HTML Base Element.
+ *
+ * Reference:
+ * https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base.
+ */
+export default class HTMLBaseElement extends HTMLElement {
+    /**
+     * Returns href.
+     *
+     * @returns Href.
+     */
+    get href() {
+        if (!this.hasAttribute('href')) {
+            return this[PropertySymbol.ownerDocument].location.href;
+        }
+        try {
+            return new URL(this.getAttribute('href'), this[PropertySymbol.ownerDocument].location.href)
+                .href;
+        }
+        catch (e) {
+            return this.getAttribute('href');
+        }
+    }
+    /**
+     * Sets href.
+     *
+     * @param href Href.
+     */
+    set href(href) {
+        this.setAttribute('href', href);
+    }
+    /**
+     * Returns target.
+     *
+     * @returns Target.
+     */
+    get target() {
+        return this.getAttribute('target') || '';
+    }
+    /**
+     * Sets target.
+     *
+     * @param target Target.
+     */
+    set target(target) {
+        this.setAttribute('target', target);
+    }
+    /**
+     * @override
+     */
+    [PropertySymbol.cloneNode](deep = false) {
+        return super[PropertySymbol.cloneNode](deep);
+    }
+}
+//# sourceMappingURL=HTMLBaseElement.js.map