LaunchOpts gains LaunchDir. session.Run resolves it via
workspace.ResolveLaunch, prints any fallback warning, and passes the
absolute path as the child process's working directory. Security
violations (absolute paths, .. escape) abort the session. The banner
gains a 'project dir: <name>/' line when launch_dir is set.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
DefaultShell, ExecAgent, ExecShell with prompt prefix. Banner, container notice. Tests for all helpers.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>