How remote sessions set up their stand-in gh command

In remote sessions (with CLAUDE_CODE_REMOTE set and the agent proxy turned on), Claude Code can put in place a stand-in gh command, a small program that takes the place of the GitHub command-line tool. This is set up differently now:

• Each session gets its own folder under sessions/, instead of all sharing one folder.
• In selective relay mode, where GitHub requests are not sent through the session's proxy, no stand-in is created if gh is not already installed.
• If an outer session already set up its own stand-in, Claude Code leaves it alone.
• The stand-in file is deleted by a cleanup step when it is no longer needed.
• When the gh in use is not the stand-in, the note Claude reads says it is the machine's own GitHub CLI.