Use the LGMP input queue when the host advertises transport input,
while preserving SPICE fallback through the existing input abstraction.
Claim input lazily, publish ordered full-state keyboard and mouse
reports without blocking rendering, and keep the owner lease alive.
Reserve queue capacity for discrete transitions, coalesce only motion
under pressure, and release ownership safely during idle and disconnect.
Keep the Linux-to-HID map in the client and update LGMP to the
nonblocking data-send API required by the input worker.
