feat(layout): finalize p01 and p02 changes

Complete UI foundation and app layout implementation, stabilize container health checks, and archive both OpenSpec changes after verification.

frontend/tests/component/lucide-icon.test.ts

@@ -0,0 +1,9 @@
+import { describe, expect, it } from 'vitest';
+import { Menu } from 'lucide-svelte';
+
+describe('lucide icon', () => {
+  it('exports menu icon component', () => {
+    expect(Menu).toBeDefined();
+    expect(typeof Menu).toBe('function');
+  });
+});