The api crash-looped because DATABASE_URL had an un-encoded special-char
password (@/!), so SQLAlchemy parsed part of the password as the host
("...@db" → name resolution failure).
db.py now prefers building the connection from POSTGRES_USER/PASSWORD/DB via
SQLAlchemy URL.create(), which encodes the password automatically — any
password works with no manual escaping. DATABASE_URL remains an optional
override (still must be hand-encoded if used). docker-compose now passes the
POSTGRES_* vars to the api container; DEPLOYMENT.md updated (incl. a Portainer
env-vars note).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
