Add LGProtocol as a pinned submodule and consume its KVMFR protocol
definitions throughout the client, host, IDD, OBS, and profiler.
Keep Looking Glass framebuffer helpers local while removing duplicated
protocol headers and migrating users to KVMFR-scoped types.
Define a fixed, protocol-independent recovery ABI in the final 64 KiB
of IVSHMEM.
Provide crash-safe multi-client requests and coherent producer status.
Exclude the region from LGMP allocation and frame capacity so future
protocol mismatches retain a stable control path.
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.
