baseimage-gui creates the app user (UID 1000) at runtime with
shell=/sbin/nologin and home=/dev/null. VSCode tries to spawn the
user's login shell for terminals, which fails with exit code 1.
Adds a cont-init script that runs as root after baseimage-gui's
adduser step and corrects both the shell and home directory.
Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)
Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>
