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/app-layout.test.ts

@@ -0,0 +1,25 @@
+import { describe, expect, it } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import AppLayout, { getContentOffsetClass } from '../../src/lib/components/layout/AppLayout.svelte';
+
+describe('AppLayout component', () => {
+  it('exports a component module', () => {
+    expect(AppLayout).toBeDefined();
+  });
+
+  it('renders children via slot', () => {
+    const source = readFileSync(
+      resolve(process.cwd(), 'src/lib/components/layout/AppLayout.svelte'),
+      'utf-8'
+    );
+
+    expect(source).toContain('<slot />');
+  });
+
+  it('maps sidebar states to layout offsets', () => {
+    expect(getContentOffsetClass('expanded')).toBe('md:ml-60');
+    expect(getContentOffsetClass('collapsed')).toBe('md:ml-16');
+    expect(getContentOffsetClass('hidden')).toBe('md:ml-0');
+  });
+});