Add wWaylandKeyPress(keycode, modifiers) to event.c/h: scans
wKeyBindings and dispatches a subset of WM shortcuts (miniaturize,
hide, maximize, raise/lower, close, focus-next/prev, workspace switch)
using raw XKB keycode + modifier values instead of an XEvent.
In wl_backend.c, wire handle_keyboard_key and handle_keyboard_modifiers
listeners on the headless keyboard device so that:
- key events are checked against WM shortcuts first
- non-shortcut keys are forwarded to the focused client via
wlr_seat_keyboard_notify_key
- modifier changes are always notified via wlr_seat_keyboard_notify_modifiers
The headless backend doesn't generate real key events so the listener
is a no-op in the smoke test, but the infrastructure is ready for a
real DRM+libinput backend.
Smoke test: check for "keyboard key+modifiers listeners wired" log.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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