Make CSRWLock own the native lock and provide scoped guards for shared,
exclusive, early-unlock, and non-blocking use.
Replace direct SRW lock management throughout the IDD, input driver,
and helper while preserving the existing lock scopes.
Add an optional input transport and a dedicated LGMP receiver that
validates source ownership, generations, ordered sequences, and leases.
Poll input outside the 10 ms control timer. Forward mouse and keyboard
state through the LGInput pipe, and neutralize the endpoint before
ownership changes or transport failures can leave input held.
Introduce transport, frame, and control interfaces with an LGMP factory
backend.
Move LGMP and IVSHMEM implementation details under transport/lgmp and
expose direct frame-buffer memory through a neutral capability.
