cmd/migratecheck — run the real migration against a throwaway Postgres.

The test suite never calls migrations.Migrate(): the integration tests
AutoMigrate only the models they need. So every raw statement at the end of
migrations/migrate.go — CREATE EXTENSION, the views, the indexes, the registry
seed — was unexecuted until this existed, and Migrate() logs those failures
NON-FATALLY. A broken view therefore returned "migration completed
successfully" and failed later at query time.

That is not hypothetical: it caught `bd.destinationid` (the real column is
bookingdestinationid), which would have left consignment_booking uncreated and
every query that joins through it failing in production.

Run it before shipping a migration change:

  docker run -d --name dm-testpg -e POSTGRES_PASSWORD=test -e POSTGRES_DB=logistics \
    -p 55432:5432 pgvector/pgvector:pg16
  docker exec dm-testpg psql -U postgres -d logistics -c "CREATE EXTENSION IF NOT EXISTS vector;"

  MIGRATE_CHECK_DSN="host=localhost port=55432 user=postgres password=test dbname=logistics sslmode=disable" \
    go run ./cmd/migratecheck

Check the OUTPUT, not just the exit code — Migrate() returns OK on a logged
failure. Any ❌ or ⚠️ line is a statement that did not run.

The same DSN unskips 50 Postgres integration tests:

  REGISTRY_TEST_DSN="host=localhost port=55432 user=postgres password=test dbname=logistics sslmode=disable" \
    go test ./... -count=1