Removed custom __eq__/__ne__ that allowed comparing enums to legacy string
names (e.g., Key.ESCAPE == "Escape"). Removed _legacy_names dicts and
to_legacy_string() functions. Kept from_legacy_string() in PyKey.cpp as
it's used by C++ event dispatch. Updated ~50 Python test/demo/cookbook
files to use enum members instead of string comparisons. Also updates
grid.position -> grid.pos in files that had both types of changes.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>