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>

app/routes/admin.py

@@ -0,0 +1,131 @@
+from flask import Blueprint, request, jsonify, session
+from app.services.nextcloud import NextcloudClient
+from config import Config
+import base64
+
+bp = Blueprint('admin', __name__, url_prefix='/api/admin')
+
+def _get_nc_client():
+    """Get authenticated Nextcloud client from session."""
+    if 'username' not in session or 'password' not in session:
+        return None
+    
+    username = session['username']
+    password = base64.b64decode(session['password'].encode()).decode()
+    
+    return NextcloudClient(Config.NEXTCLOUD_URL, username, password)
+
+def _check_admin():
+    """Check if current user has admin privileges."""
+    if not session.get('is_admin', False):
+        return False
+    return True
+
+@bp.route('/users', methods=['GET'])
+def list_users():
+    """List all Nextcloud users (admin only)."""
+    if not _check_admin():
+        return jsonify({'error': 'Admin privileges required'}), 403
+    
+    nc_client = _get_nc_client()
+    if not nc_client:
+        return jsonify({'error': 'Not authenticated'}), 401
+    
+    result = nc_client.ocs_get_users()
+    
+    if not result.get('success'):
+        return jsonify({'error': result.get('error', 'Failed to list users')}), 500
+    
+    return jsonify(result), 200
+
+@bp.route('/users', methods=['POST'])
+def create_user():
+    """Create a new Nextcloud user (admin only)."""
+    if not _check_admin():
+        return jsonify({'error': 'Admin privileges required'}), 403
+    
+    data = request.get_json()
+    
+    if not data or 'username' not in data or 'password' not in data:
+        return jsonify({'error': 'Username and password required'}), 400
+    
+    username = data['username'].strip()
+    password = data['password']
+    email = data.get('email', '').strip()
+    displayname = data.get('displayName', '').strip()
+    groups = data.get('groups', [])
+    
+    if not username or not password:
+        return jsonify({'error': 'Username and password cannot be empty'}), 400
+    
+    nc_client = _get_nc_client()
+    if not nc_client:
+        return jsonify({'error': 'Not authenticated'}), 401
+    
+    result = nc_client.ocs_create_user(
+        username=username,
+        password=password,
+        email=email if email else None,
+        displayname=displayname if displayname else None,
+        groups=groups if groups else None
+    )
+    
+    if not result.get('success'):
+        return jsonify({'error': result.get('error', 'Failed to create user')}), 500
+    
+    return jsonify(result), 201
+
+@bp.route('/users/<username>/enable', methods=['PUT'])
+def enable_user(username):
+    """Enable a user account (admin only)."""
+    if not _check_admin():
+        return jsonify({'error': 'Admin privileges required'}), 403
+    
+    nc_client = _get_nc_client()
+    if not nc_client:
+        return jsonify({'error': 'Not authenticated'}), 401
+    
+    result = nc_client.ocs_enable_user(username)
+    
+    if not result.get('success'):
+        return jsonify({'error': result.get('error', 'Failed to enable user')}), 500
+    
+    return jsonify(result), 200
+
+@bp.route('/users/<username>/disable', methods=['PUT'])
+def disable_user(username):
+    """Disable a user account (admin only)."""
+    if not _check_admin():
+        return jsonify({'error': 'Admin privileges required'}), 403
+    
+    nc_client = _get_nc_client()
+    if not nc_client:
+        return jsonify({'error': 'Not authenticated'}), 401
+    
+    result = nc_client.ocs_disable_user(username)
+    
+    if not result.get('success'):
+        return jsonify({'error': result.get('error', 'Failed to disable user')}), 500
+    
+    return jsonify(result), 200
+
+@bp.route('/users/<username>', methods=['DELETE'])
+def delete_user(username):
+    """Delete a user account (admin only)."""
+    if not _check_admin():
+        return jsonify({'error': 'Admin privileges required'}), 403
+    
+    # Prevent self-deletion
+    if username == session.get('username'):
+        return jsonify({'error': 'Cannot delete your own account'}), 400
+    
+    nc_client = _get_nc_client()
+    if not nc_client:
+        return jsonify({'error': 'Not authenticated'}), 401
+    
+    result = nc_client.ocs_delete_user(username)
+    
+    if not result.get('success'):
+        return jsonify({'error': result.get('error', 'Failed to delete user')}), 500
+    
+    return jsonify(result), 200