Remove numlockx dependency

[lenemter]

numlockx only woks on X11

[atharvafulay]

Hi! I’d like to work on this.

My proposed scope is to remove the X11-only numlockx process invocation, the now-unused activate_numlock setting/property, and its sample configuration entry, while leaving the Num Lock state indicator untouched. I’ll keep the patch limited to this obsolete integration, build it with Meson, and run the repository’s available checks.

Please let me know if you want to retain the configuration key for compatibility; otherwise I’ll remove the full dead path so the fix does not leave an inert setting behind.