The initialisation of DB, error in docker-entrypoint-initdb.d

Hello.

It appears, I have found an error in docker-entrypoint-initdb.d (each SHs).
The connection to Postgres is incorrect
`psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER"`

should be
`psql -v ON_ERROR_STOP=1 --username="$POSTGRES_USER" --dbname="$POSTGRES_DB"`
or
`psql -v ON_ERROR_STOP=1 -U "$POSTGRES_USER" -d "$POSTGRES_DB"`
[psql](https://www.postgresql.org/docs/17/app-psql.html)

With this CLI
`psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER"`
_"$POSTGRES_USER"_ are handled as _"dbname"_

It works with the default _.env.example_ because
default _'POSTGRES_USER'_ is _'postgres'._
default _'POSTGRES_DB'_ is _"$POSTGRES_USER"_
[postgres Docker Official Image](https://github.com/docker-library/postgres/blob/2925b19f45ceeb8ab8488eec226f2736abf297e1/17/trixie/docker-entrypoint.sh#L234-L238)

So, it works
```
POSTGRES_USER=postgres
POSTGRES_DB=postgres
```
Related issues:
[Won't start up](https://github.com/ckan/ckan-docker/issues/74)
[Docker Compose - Error while starting DB container](https://github.com/ckan/ckan-docker/issues/73)

Start in docker-entrypoint-initdb.d and inspect each shell script that invokes psql; compare those commands with the .env.example defaults and PostgreSQL's documented argument handling. Verify the scripts with distinct POSTGRES_USER and POSTGRES_DB values, and consider the work done when initialization connects to the configured database rather than treating the user as the database.

Written by the indexing model from the issue text.