Instrument redraw sources, per-output request coalescing, and animation fallback scheduling. Route local visual changes to their affected outputs while preserving deferred grab and gesture updates.
Schedule fallback recovery using each orphaned animation output's refresh interval, suppress it while a normal frame chain exists, and retain requested final frames after scheduling failures. Add mixed-refresh, cursor footprint, frame-chain, and disconnect regressions and document measurement limits.
Render selected toplevels through a private portal-only capture protocol, preserve logical snapshot geometry, and renegotiate PipeWire video on window resizing. Bound outstanding snapshots and retry temporary contention; stop on source closure and session locking.
Validation: portal unit tests (31), capture budget unit, private-bus portal contracts, and real nested/PipeWire isolation, workspace, resize, close and paused-lock tests pass. Independent review cleared. Monitor restore integration timed out on both this build and the unchanged previous compositor under the current nested host.