void deploy: option to deploy without applying migrations #469

What

void deploy always applies pending migrations before the new version goes live, and no documented flag turns that off (Deployment › Migrations, CLI: deploy).

We deploy code without migrating in two cases:

• Pull request previews share one database, and a pull request's code must not migrate it.
• Production migrates in its own gated step, so the person promoting a release decides when the schema changes.

Done when

void deploy can ship a new version without applying pending migrations.