Run a shell command inside the project's devcontainer and return its combined stdout/stderr and exit status.

Mirrors Claude Code's built-in Bash tool, but every command executes inside the devcontainer (via devcontainer exec ... bash -lc) rather than on the host. Use it for builds, tests, package installs and any other shell work that should happen in the container environment.

The command string is interpreted by bash inside the container, so pipes, &&, ||, globs, redirects, env expansion and quoting all behave as in a normal shell.