fix(shortcuts): make extension shortcuts local, add local fallback for cmd
Most extension shortcuts (hud, editor, groups, tags, timers, feeds,
lists, pagestream, windows, tag-actions) were registered as global
OS hotkeys which fail silently on Linux Wayland. Changed them to local
shortcuts that work reliably when the app has focus.
Cmd palette shortcut (Option+Space) is now registered as both global
and local, so it works on Linux even when global registration fails.