Add NextSnap PWA with photo gallery viewer and continuous capture

Offline-first photo capture app for Nextcloud with:
- Camera capture with continuous mode (auto-reopens after each photo)
- File browser with fullscreen image gallery, swipe navigation, and rename
- Upload queue with background sync engine
- Admin panel for Nextcloud user management
- Service worker for offline-first caching (v13)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_health.py

@@ -0,0 +1,22 @@
+import pytest
+from app import create_app
+
+@pytest.fixture
+def app():
+    """Create application for testing."""
+    app = create_app('development')
+    app.config['TESTING'] = True
+    return app
+
+@pytest.fixture
+def client(app):
+    """Create test client."""
+    return app.test_client()
+
+def test_health_endpoint(client):
+    """Test the health check endpoint."""
+    response = client.get('/api/health')
+    assert response.status_code == 200
+    data = response.get_json()
+    assert data['status'] == 'healthy'
+    assert data['service'] == 'nextsnap'