Devcontainer setup broken because of Postgresql v18

Devcontainer fails to start after upgrading to PostgreSQL 18. The database container enters a restart loop because PostgreSQL 18+ expects data to be mounted at /var/lib/postgresql instead of /var/lib/postgresql/data. The existing volume contains data from an older PostgreSQL version in the old directory structure, causing the container to crash on startup with the error "cannot join network namespace of container: Container is restarting, wait until the container is running".