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/eslint-plugin-svelte/lib/configs/flat/all.js

@@ -0,0 +1,15 @@
+import { rules } from '../../utils/rules.js';
+import base from './base.js';
+const config = [
+    ...base,
+    {
+        name: 'svelte:all:rules',
+        rules: Object.fromEntries(rules
+            .map((rule) => [`svelte/${rule.meta.docs.ruleName}`, 'error'])
+            .filter(([ruleName]) => ![
+            // Does not work without options.
+            'svelte/no-restricted-html-elements'
+        ].includes(ruleName)))
+    }
+];
+export default config;