chore: retire legacy curve mapping

[a1denvalu3]

Summary

• remove the obsolete curve-mapping compatibility path
• use the current mapping consistently in wallet and proof verification
• add regression coverage for mapping aliases

Testing

• poetry run pytest tests/test_crypto.py tests/mint/test_mint_verification.py -q
• make check

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.49%. Comparing base (a935eb9) to head (49eef78).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1082      +/-   ##
==========================================
- Coverage   74.54%   74.49%   -0.05%     
==========================================
  Files         115      115              
  Lines       13195    13159      -36     
==========================================
- Hits         9836     9803      -33     
+ Misses       3359     3356       -3     

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