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.
Replace legacy clipboard grant and queued input fixtures with bound SPSC
stream endpoints. Verify stream-only payload delivery, credit recovery,
release completion, and four 256 KiB records for a 1 MiB response.
Keep queue assertions for status, discovery, ownership, and control.
