enum CursorBridge

Where the pointer image is actually set.

The same shape as WindowBridge and ScrollBridge: LavaUI must not know what a compositor is. A windowed app sets the cursor on its own GLFW window; a client has no pointer of its own and asks the compositor, which fills request at connect. Unfilled, the windowed path is used, which is the right default for a window and a no-op in a test.