- Added 4 missing columns to _ensure_translation_jobs_columns() inline
migration: target_language_column, target_source_column,
target_source_language_column, disable_reasoning — these were in the
SQLAlchemy model but had no Alembic migration or _ensure_*() coverage
- Added missing api_key, assistant, clean_release model imports to
alembic/env.py so autogenerate can see all tables