CLI install path for optional deepagents-code extras.
dcode install <name> installs a curated optional extra (for example a sandbox
or model-provider dependency) into the current dcode environment. The legacy
global flags dcode --install <name> / --package / --yes remain as
compatible aliases and call the same implementation.
tools install is intentionally separate: that group provisions managed host
binaries (ripgrep), while this command manages Python package extras for dcode.
Help rendering for dcode install -h is served by ui.show_install_help, which
does not import this module, so the help path stays light.
Dispatch dcode install <name>.
Install an optional extra or an arbitrary package via uv --with.
Shared by dcode install and the legacy dcode --install flag.
