refactor: move frontend/ to examples/frontend/

The Lit + Vite HOMECORE web UI is an example consumer of the
sensing stack, not a top-level deliverable — relocate it under
examples/ alongside the other sensor and dashboard demos.

Add an entry to examples/README.md so it's discoverable.

Co-Authored-By: claude-flow <ruv@ruv.net>

examples/frontend/src/__tests__/client.test.ts

@@ -0,0 +1,67 @@
+/**
+ * Unit tests for HomecoreClient REST methods.
+ * Mocks global `fetch` and asserts correct URL + Authorization header.
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { HomecoreClient } from '../api/client.js';
+
+describe('HomecoreClient', () => {
+  const token = 'test-bearer-token';
+  let client: HomecoreClient;
+  let fetchSpy: ReturnType<typeof vi.fn>;
+
+  beforeEach(() => {
+    client = new HomecoreClient({ token });
+    fetchSpy = vi.fn().mockResolvedValue({
+      ok: true,
+      json: () => Promise.resolve([]),
+    } as Response);
+    vi.stubGlobal('fetch', fetchSpy);
+  });
+
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it('getStates() GETs /api/states with the bearer header', async () => {
+    await client.getStates();
+
+    expect(fetchSpy).toHaveBeenCalledOnce();
+    const [url, init] = fetchSpy.mock.calls[0] as [string, RequestInit];
+
+    expect(url).toBe('/api/states');
+    expect((init.headers as Record<string, string>)['Authorization']).toBe(`Bearer ${token}`);
+    expect(init.method).toBe('GET');
+  });
+
+  it('getState() GETs /api/states/:entity_id with the bearer header', async () => {
+    fetchSpy.mockResolvedValueOnce({
+      ok: true,
+      json: () => Promise.resolve({ entity_id: 'light.living', state: 'on', attributes: {}, last_changed: '', last_updated: '', context: { id: 'x', user_id: null, parent_id: null } }),
+    } as Response);
+
+    await client.getState('light.living');
+
+    const [url] = fetchSpy.mock.calls[0] as [string, RequestInit];
+    expect(url).toBe('/api/states/light.living');
+  });
+
+  it('getConfig() GETs /api/config', async () => {
+    fetchSpy.mockResolvedValueOnce({
+      ok: true,
+      json: () => Promise.resolve({ location_name: 'Home', version: '0.1.0', state: 'RUNNING', components: [] }),
+    } as Response);
+
+    await client.getConfig();
+
+    const [url] = fetchSpy.mock.calls[0] as [string, RequestInit];
+    expect(url).toBe('/api/config');
+  });
+
+  it('throws on non-OK response', async () => {
+    fetchSpy.mockResolvedValueOnce({ ok: false, status: 401, statusText: 'Unauthorized' } as Response);
+
+    await expect(client.getStates()).rejects.toThrow('401');
+  });
+});