mft-new-migration

name	mft-new-migration
description	Generate and hand-review a new Alembic migration after editing SQLModel tables.

Use when the user asks to add or change a database table.

1. Edit the SQLModel definition under backend/src/my_family_tree/models/. If you added a new aggregate, also add it to models/__init__.py.
2. Run make migration M="add <thing>". This calls alembic revision --autogenerate.
3. Hand-review the generated migration:
   • Confirm enum types are referenced via models.enums (don't recreate them).
   • Confirm vector columns use Vector(N) and HALFVEC(N) from db.types.
   • For HNSW or trigram indexes, add op.execute("CREATE INDEX ...") because autogenerate doesn't emit them.
   • For composite-PK tables (event_participant, conflict_claim), make sure the FK constraints are declared via op.execute("ALTER TABLE ...") since SQLModel can't express them inline.
4. make migrate to apply.
5. If your change is destructive (dropping a column, narrowing a type), document the intentional drop in the migration's docstring and add a note to the PR body.