enrich: use python 3.13 (dbt doesn't support 3.14 yet)
dbt-core pins mashumaro<3.15 and uses pydantic v1 shim, both broken
on 3.14. override enrich's command to --python 3.13 while other flows
stay on 3.14. nice demo of per-deployment flexibility via job_variables.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>