fix: add name property to OpCode for mypy not to complain when accessing it

[toby-bro]

Mypy kept complaining when I accessed the name attribute of OpCode even though it is present in the C++ code (thanks to nanobind nb::enum_ type)
So made it a class property.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.57%. Comparing base (7b16cb0) to head (bcd6535).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #252   +/-   ##
=======================================
  Coverage   86.57%   86.57%           
=======================================
  Files           5        5           
  Lines         514      514           
  Branches       82       82           
=======================================
  Hits          445      445           
  Misses         27       27           
  Partials       42       42           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[mborgerson]

Thanks!