Report Phase working/idle state to Herdr

[maxBRT]

Summary

Ship Phases no longer rely on Cursor screen-detection cues for multiplexer sidebars. When HERDR_ENV / HERDR_SOCKET_PATH / HERDR_PANE_ID are set, the Run orchestrator reports working at Phase start (with the same Iteration · Phase · Ticket label as the throbber) and idle on every exit path via herdr pane report-agent. Outside Herdr the reporter is a no-op, so normal terminals and CI are unchanged.

Linked issues

• Report agent state to Herdr (and similar multiplexers) during Phases #57: Report agent state to Herdr (and similar multiplexers) during Phases

RISK

• Stale working state in Herdr sidebar (low–medium): if Ship is killed hard (SIGKILL) mid-Phase, the deferred idle report never runs and the Agents row can stay on working until Herdr’s own timeout/fallback. Affected: operators watching Ship inside a Herdr pane.
• Wrong or missing sidebar status if Herdr CLI/env contract drifts (low): reports shell out to herdr (or HERDR_BIN_PATH). A breaking CLI change or incomplete env still no-ops or fails best-effort and does not Abort the Run, but the sidebar may stay wrong. Affected: Herdr users only.
• Brief herdr process spawn per Phase boundary (very low): each Working/Idle call execs the CLI when under Herdr. Unlikely to matter unless Phase boundaries are extremely frequent; does not change Agent work itself.

QA — stress-test plan for a human

1. Happy path

   • Outside Herdr: go test ./..., staticcheck ./..., and a normal ship Run (or --help / dry queue) in a plain terminal. Confirm no herdr invocations and no behavior change on the throbber (Iteration N · Phase · #ticket).
   • Inside a Herdr pane with HERDR_ENV=1, HERDR_SOCKET_PATH, and HERDR_PANE_ID set: start a Run that reaches at least one Implement Phase (ship-labeled Ticket, confirm queue). While the Phase is running, check the Agents sidebar: Ship/ship:run should show working with a message like Iteration 1 · Implement · #<n> …. When the Phase ends (success), it should return to idle. Repeat for Review and Final if the Run gets that far.

2. Edges / failure cases

   • Force an Abort mid-Phase (bad Agent, kill the nested agent, or a short timeout): sidebar must still flip to idle after Ship Aborts; unfinished Tickets keep the ship label as before.
   • Under Herdr env but with herdr missing from PATH (or a broken HERDR_BIN_PATH): Run must still complete / Abort normally; missing CLI must not fail the Phase.
   • Partial Herdr env (e.g. HERDR_ENV=1 without HERDR_PANE_ID): must no-op like outside Herdr.
   • Concurrent: leave Ship working in one pane and confirm other panes’ agent rows are unaffected.

3. Out of scope

   • Cursor screen-manifest TOML tuning, Pi lifecycle hooks, queue picker UX, Implement/Review prompt content, and PR-body wording from Final (unchanged by this branch).