Add regex_engine="python-re" if regex uses lookaround

[camillol]

Pydantic 2 uses Rust's regex implementation by default, which runs in linear time but doesn't support lookarounds or backreferences. If a field needs to use such a regex, it is necessary to set up the model's config to use Python's regex engine instead. See documentation.

This change adds the necessary config when generating Pydantic 2 models that contain a field with a pattern containing lookarounds.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Please upload report for BASE (main@fcab9a4). Learn more about missing BASE report.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1945   +/-   ##
=======================================
  Coverage        ?   98.47%           
=======================================
  Files           ?       37           
  Lines           ?     4189           
  Branches        ?      974           
=======================================
  Hits            ?     4125           
  Misses          ?       47           
  Partials        ?       17           

Flag	Coverage Δ
unittests	98.13% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #1945 will not alter performance

_{Comparing camillol:regex_engine (cdcd01d) with main (fcab9a4)}

Summary

✅ 29 untouched benchmarks