Two capture bugs compounding into 'sluggish and not captured':
1. flush_motion was never called from the run loop — the GTK client's
frame-clock tick flushed pending motion every frame, and the port
lost it. Pure mouse movement only reached the host when a click/key/
scroll happened to flush it; the host cursor simply didn't follow.
Now one coalesced MouseMove per loop iteration.
2. Capture forwarded ABSOLUTE letterboxed coordinates with no pointer
confinement (GTK parity, the plan's deferred 'stage-2' item): the
visible local cursor outran the host cursor by the full e2e and
escaped the window. Capture is now real pointer lock — SDL relative
mouse mode (hidden, confined, raw deltas) with relative MouseMove on
the wire, so the host cursor is the only cursor.
Also: focus-gain re-engages after an auto-release (Alt-Tab undoes
itself; the startup focus race can no longer strand the session
uncaptured) while a chord release stays released until the user opts
back in.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
enricobuehler
a5bb5ec4d5