- Use setting.Database.Type.IsSQLite3() / IsMySQL() for dialect checks
to match the rest of models/migrations/.
- Trim the migration's comment to the load-bearing why (MSSQL rejects
inline DEFAULT, MySQL drops it on MODIFY COLUMN), drop the discovery
narrative.
- Trim test comments and tighten the type-name assertion list to the
values dialects actually emit (verified empirically against the CI
image versions: MySQL/MSSQL report "INT", Postgres reports "INTEGER";
"INT4" never surfaces, removed).
Re-tested against postgres:14, bitnamilegacy/mysql:8.0, mssql:2019-latest,
and SQLite — all pass.
Co-Authored-By: Claude (Opus 4.7) <noreply@anthropic.com>