allow migrations through env var

instead of deciding if we want to always perform migrations or if we want to block them, we could have them be gated by an environment variable, so that we can change the behavior if needed, and especially decide if we want them to run only on production or on staging too

The issue names no files or tests; first locate the migration startup and configuration entry points, then review how deployment environments distinguish production from staging. Clarify the environment variable’s values and defaults, and consider the work done when migrations can be enabled or blocked per environment as requested.

Written by the indexing model from the issue text.