herdr: what the bundled skill leaves out

Before you use this skill, check that HERDR_ENV=1. If it is not 1, tell the user that you do not run inside a herdr pane. Then stop.

Run herdr --skill first. It prints the command surface for the installed version, so it is never stale. Print a command group's syntax by running it without a subcommand (herdr agent, herdr pane, herdr worktree); bare herdr launches the TUI. This skill carries only what those two leave out.

Handles

Ids are opaque: read every id from a live command. A closed tab or pane id is not reused, so a stale pane id resolves to nothing rather than to the wrong agent. herdr pane move into another workspace gives the pane a new id; continue with .result.move_result.pane.pane_id, or with the agent's name.

An agent has three handles of different durability: