Migration filename collisions (0013, 0017, 0020 each used twice)
Imported from GitHub issue El-SaMa/oma#100 by @El-SaMa.
`packages/db/migrations/` has duplicate version prefixes:
- `0013_platform_settings.sql` and `0013_support_and_settings.sql`
- `0017_platform_api.sql` and `0017_support_tickets_desk.sql`
- `0020_support_form.sql` and `0020_whmcs_external_ids.sql`
The migration runner currently tolerates this (sorts by full filename, not just the numeric prefix), but it's a footgun for ordering assumptions and makes the history harder to read. Renumber going forward; consider a CI check that fails on duplicate numeric prefixes.