Update cameras

Update one or more cameras.

Update configuration, credentials, feature flags, and group assignments for one or more cameras. Each camera is updated independently - if one camera's update fails, others can still succeed. Within each camera's update, all changes are atomic.

Group Assignment:

• Provide group_ids to assign the camera to specific groups
• An empty list [] resets the camera to the default group
• Omit group_ids (null) to leave group assignments unchanged