docker-compose.yml passed POSTGRES_PASSWORD as APP_DB_PASSWORD, so the DML-only
dtf_app role and the owning administrator shared one credential and the
privilege separation bootstrap.py sets up was decorative.
APP_DB_PASSWORD is now its own required variable, and bootstrap refuses to run
when it matches the administrator password, in both the URL and discrete-field
configuration forms.
Deploying this requires APP_DB_PASSWORD to be set in the stack environment
first; db-init rotates the role to it on the same deploy.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
