Agent-pushed status chips in the sidebar row via OSC 9001 (token.<name>=…, with TTL) #172

This was generated by AI during triage.

Summary

Let the program in a session push small status chips into its sidebar row (and the toolbar), e.g. tests 12/40, PR #82, deploying. Each chip has an optional time-to-live, so a stale one disappears on its own.

Motivation

OSC 9001 already lets a session set its title, colour, branch and dirty flag. Agents and hooks often have one more fact worth showing at a glance — progress, the current task, the PR number — and today the only option is to stuff it into the title.

Herdr (pane report-metadata, v0.9.0–v0.9.1):

• --token key=value sets display-only tokens, with --ttl-ms for expiry;
• --state-label state=text renames a state's label;
• sidebar rules can recolour, bold, dim or hide tokens based on their value.

Tokens are visual only. Waits, notifications and roll-ups still use the semantic state.

Proposal

• Wire format. New OSC 9001 keys: token.<name>=<value> (an empty value removes the chip) and token-ttl=<seconds>, which applies to the tokens in the same sequence.
• Validation in ShellIntegrationPayload:
  • token names [a-z0-9-]{1,16};
  • values stripped of control characters and capped (~24 chars);
  • at most 4 tokens per session;
  • TTL capped (e.g. 24h).
• Display. Chips render after the branch in the sidebar row and in the terminal toolbar, in a muted pill style using Catppuccin colours.
• Lifetime. Chips live in memory only and are not persisted. A restart clears them, which is what you want for "deploying".
• No colour rules in v1. If a chip needs emphasis, the agent can push the accent via color=.

Related: #161 (kanban cards can show the chips), #138 (Team Bus), docs/shell-integration.md.