On RemoteDesktop-capable desktops (KWin, GNOME), select the ScreenCast source on
a session created via the RemoteDesktop portal and start it through RemoteDesktop,
so a single grant — pre-authorized headlessly via the `kde-authorized` permission,
exactly like the libei input path — also covers screen capture. Standalone
ScreenCast has no such bypass and would raise an un-clickable dialog on a headless
box. wlroots/Sway has no RemoteDesktop portal, so it keeps the plain ScreenCast
session; the choice keys off inject::default_backend(). The PipeWire consumer is
unchanged — the anchored session yields the same fd + node id.
Validated on headless KWin (Plasma 6.4): the portal grants the session with no
dialog and PipeWire negotiates the format (1920x1080 BGRx, Streaming). Frame
delivery on KWin still pends dmabuf import — KWin hands GPU dmabuf buffers and the
M0 consumer is CPU-copy/shm only (plan §9, zero-copy) — so it's the next step;
the CPU-copy path remains correct on wlroots.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
0a79a8209b