/claim #8031

## Attempt — Implementation plan for #8031

Scope (per bounty): Make clipboard sharing work on Wayland on GNOME (Mutter) and KDE (KWin) via XDG portals; land needed changes in portal backends/compositors and integrate Deskflow. No extra “enterprise” features.

Flow (now): RemoteDesktop + Clipboard

• Create RemoteDesktop session; before Start(), call org.freedesktop.portal.Clipboard.RequestClipboard(session) (spec requires before start).
• Implement: SetSelection (advertise MIME types), handle SelectionOwnerChanged / SelectionTransfer, implement SelectionRead, SelectionWrite, SelectionWriteDone.
• Files later via FileTransfer (^Gpplication/vnd.portal.filetransfer) after parity on other platforms.

Backends:

• xdg-desktop-portal-gnome and xdg-desktop-portal-kde implement/verify Clipboard portal, talking to the compositor via ext-data-control-v1.

Compositors:

• Ensure KWin and Mutter expose the required data‑control hooks used by the portal backends (ext‑data‑control‑v1).

Deskflow integration:

• Use QDBus to call org.freedesktop.portal.Clipboard.* on org.freedesktop.portal.Desktop at /org/freedesktop/portal/desktop. Keep libportal for other portals if desired.

Acceptance checks (both GNOME & KDE):

• Bidirectional copy/paste of text/plain, text/html, image/png
• Large payloads; rapid ownership churn; short demo video included
• Troubleshooting notes for portal/backend selection

Deliverables:

• Upstream MRs: GNOME portal backend, KDE portal backend, KWin/Mutter (if needed)
• Single Deskflow PR linking all MRs; CI green; demo video and repro steps

Spec references for reviewers:
• Clipboard.RequestClipboard “This request must be made before the session starts … see Remote Desktop to integrate clipboard.” :contentReference[oaicite:1]{index=1}
• RemoteDesktop.Start and session flow (Clipboard enabled via RequestClipboard). :contentReference[oaicite:2]{index=2}
• ext‑data‑control‑v1 gives the portal backend privileged clipboard control. :contentReference[oaicite:3]{index=3}