AAI-119 fix alembic not handling enum in migrations

[marius-mather]

Description

AAI-119: reworking migrations: alembic is a bit finicky about Enum types, so easier to reset the migrations and start again than fix them. Also adding a GitHub Action to check migrations so we don't get caught by this again

Changes

• Reset migrations and generate a new one - Enums work automatically when creating a new table
• Add GitHub Action to check migrations so we don't break them

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have added unit / integration tests that prove my fix is effective or that my feature works
• I have run all tests locally and they pass
• I have updated the documentation (if applicable)

How to Test Manually (if necessary)

Run uv run python generate_migrations.py --check

[amandazhuyilan]

Nothing to complain :)