Renew the frame-schedule lease only while the display server is
producing real cadence callbacks. Release ownership after the cadence
stalls, and reacquire with an immediate reset when it resumes.
For non-JIT rendering, treat only a successful presentation as live
cadence.
Bump KVMFR to version 28 and attach generation, epoch, and deadline
identities to cadence deliveries and their timing records.
Accept phase corrections only for the exact completed publication. Keep
VM and client clocks independent by exchanging relative phase errors.
Make submission, completion, and work-estimate accounting best effort
so scheduler state cannot delay GPU submission or frame publication.
Always track Wayland surface outputs alongside fractional scaling and use
RandR modes for X11 cadence. Remove render-derived feedback so a
throttled client cannot teach the producer to remain throttled.
Release scheduling after nominal output timing remains unavailable.
