The GTK mouse handlers now delegate to *_impl methods taking button and
modifier state, so the real controllers and the debug input replay share
one code path. The replay hook gained mouse-move/press/release, click,
drag, scroll, resize, clipboard-set/dump, windows-dump and
window-screenshot steps (replayed presses bypass the focus-transfer
first-click rule since the replay window isn't compositor-focused).
Verified in the real app on Wayland (docs/rewrite/notes/verification-
V3.md): nvim (colors, status line, cursor shapes, alt-screen restore),
htop (rendering, mouse-click column sorting), less (alternate scroll),
tmux (splits, status bar), drag/double/triple-click selection into
PRIMARY, clipboard copy, context menu, scrollback and reflow on resize,
CJK/emoji/ZWJ/nerd-font widths, kitty graphics images and the unsafe
paste confirmation dialog. No product bugs were found.
Test Plan:
- cargo test -p ghostty-apprt-gtk (incl. parse_mouse_steps)
