walnut-session-messaging

# Talking to the user's other sessions Two operations cover everything: `session_list` finds sessions, `session_send` talks to one. Both go through `walnut tools call`, which works from any Walnut-managed session on any host and from a plain terminal. The old `walnut peers` commands were removed in 2026-08. `walnut peers` now exits with a usage error naming the replacements, so an old habit fails loudly instead of doing nothing: | Old command | Call this instead | |---|---| | `walnut peers list` | `walnut tools call session_list '{}'` | | `walnut peers send <target> <text>` | `walnut tools call session_send '{"to":"<target>","text":"..."}'` | ## Zero configuration - Inside a session Walnut launched, `walnut` is already on the PATH and uses the injected `WALNUT_AGENT_SOCKET` + `WALNUT_SESSION_ID`. - Started by hand (a plain terminal, an agent you launched yourself), `walnut` falls back to this host's own daemon socket and identifies as an external caller. Same commands, same capabilities; only the sender label differs, because there is no session to name. If `walnut` is not on your PATH, the daemon also installs it at `~/.local/bin/walnut`. ## Discover ```bash walnut tools call session_list '{}' # the user's sessions across all hosts walnut tools call session_list '{"status":"running"}' # running | idle | stopped | error ``` ## Send ```bash walnut tools call session_send '{"to":"9f3a","text":"auth fixture refactor is merged on main; rebase befor...