The container still exited immediately after the su-based fix. can
interfere with TTY/stdin handling for interactive shells. Switch to
, which is root-only, skips PAM, and preserves file descriptors so
bash stays interactive.
Also improve container failure diagnostics:
- now combines stdout and stderr
- This helps surface the real reason when a container exits with code 0
Quality gates:
- pytest tests/unit: 219 passed
- ruff: clean on changed files
- mypy: clean on changed files