Apply all pending, already-committed migrations to a production/staging/CI database using prisma migrate deploy, without generating new migrations or touching a shadow database.

Documented steps

1. Ensure the target environment has prisma.config.ts (or a per-environment config file such as prisma.config.prod.ts) with datasource.url pointing at the production connection string, typically via env("DATABASE_URL").
2. Ensure the prisma/migrations directory (committed to source control) is present in the deploy environment/CI image alongside prisma.config.ts.
3. Run `npx prisma migrate deploy` (add `--config prisma.config.prod.ts` if using a non-default config path, or `--schema` for a non-default schema path). This applies all migrations not yet recorded in the _prisma_migrations table, in order, and creates the database if it doesn't exist.
4. migrate deploy does not run prisma generate — run `npx prisma generate` as a separate build step (commonly in a postinstall or CI build script) so the deployed app has an up-to-date Prisma Client.
5. Wire this into CI/CD, e.g. run `npx prisma migrate deploy` as a release step before starting the app, and check the exit code — a non-zero exit means a migration failed and must be resolved before the app starts.
6. Reference: https://www.prisma.io/docs/cli/migrate/deploy