Move handler trait impls and delegate macros from state.rs into
handlers/{compositor,xdg_shell,input,output}.rs. Flesh out
CompositorHandler::commit with on_commit_buffer_handler and
XdgShellHandler::new_toplevel with window mapping. Add DataDeviceHandler,
SelectionHandler, ClientDndGrabHandler, and ServerDndGrabHandler impls
with DataDeviceState in the WayRay struct. State.rs now contains only
the struct definition and constructor.
Define the central WayRay state struct holding all Smithay subsystem
states (compositor, xdg_shell, shm, seat, output, space, clock) and
wire Display creation into main.rs. Includes minimal handler trait
impls and delegate macros needed to compile; these will be expanded
and moved to a handlers module in Task 4.
