* fix(keyboard): support AltGr (ISO_Level3_Shift) for Right Alt on int'l keyboards
On UK/International keyboards, Right Alt (AltGr) sends ISO_Level3_Shift
(keysym 0xfe03) instead of Alt_R (keysym 0xffea). The pynput backend
was only checking for keyboard.Key.alt_r, missing the alt_gr key that
pynput uses for ISO_Level3_Shift.
Changes:
- Add keyboard.Key.alt_gr to MODIFIER_NORMALIZE_MAP (normalizes to alt)
- Include alt_gr in the "alt" and "right_alt" key variants
- Update side-specific matching to check key variants instead of
exact key comparison
Fixes#322
* fix(keyboard): generalize pynput modifier alias matching
* test(keyboard): make variant tests independent of pynput install