ash-project/ash_postgres

AI Summary: Debug and fix a bug in the AshPostgres library where removing the `:context` multitenancy option causes invalid migrations to be generated. The issue arises when dropping foreign key constraints that no longer exist, resulting in migration failures. The provided reproduction repository should be used to identify and correct the root cause within the AshPostgres migration generation process.

AI Summary: Fix a bug in the AshPostgres migration generator where the `down` migration incorrectly orders renaming a column and changing its nullability, leading to migration failures. The solution involves reversing the order of operations in the `down` function to correctly rename the column after modifying its nullability.

AI Summary: Improve AshPostgres's `ash.codegen` to prevent the generation of empty migration files and snapshots for resources lacking attributes or relationships. The current behavior leads to errors when subsequently adding attributes and running migrations.