installEnv() only redirected NPM_CONFIG_PREFIX inside the Docker container
(CODEMAN_IN_CONTAINER=1). On a native install with a root-owned system node
(prefix /usr) `npm install -g @deepseek-ai/dsh` run as the server user died
with EACCES (exit 243), so DeepSeek, pi and other npm-based CLIs could not be
installed from Settings. Ask npm for its global prefix and, when the server
user cannot write it, redirect to $HOME/.local like the container path does.
An operator-set NPM_CONFIG_PREFIX and a writable prefix are left alone.