[coordination] Overseer delegates a GOAL to the durable Pilot (replace the one-shot)

[serge-ivo]

Near-term build — the only near-term item in #154. Also the first slice of the delegate primitive + task record (shaped to generalize; generalized only as far as this consumer forces).

Today the Overseer's drive_claude(repoId, instruction) (routes/coding.ts) sends ONE instruction to a repo's Engine and returns a reply string — no follow-through for multi-step work.

Do:

• Keep the direct Engine send for genuine one-shots ("run the tests").
• For a multi-step goal, the Overseer hands it to the repo's Pilot (CodingSessionWorkflow, durable) which owns the snapshot→decide→act loop + stuck/needs_input escalation — instead of a fire-and-forget drive_claude.
• Return a task/status handle (not just a reply string) so the coordinator can report progress. Persist it on the existing board + coding_timeline (minimal: id, repo, goal, status, result).
• Decision point: "is this a command or a goal?" — start simple (goal = default for the Overseer's DONE path; one-shot stays for read/trivial), refine later.

Keep it minimal + Coder-scoped — this is the fix as a primitive, not a framework. Behavior for one-shots unchanged; add durable follow-through for goals. Tests: goal → Pilot started + task recorded + status transitions; one-shot path unchanged.

Design: docs/coordination-primitives.md. Part of #154.

[serge-ivo]

Observability requirement (hard, not optional). Delegation must never be silent and must never masquerade as a user message.

Today driveClaude already writes an "On it —

" assistant turn to the target repo's session timeline + auto-reports completion via the finish-watcher — so it's not silent, but it lands in that specific repo's thread (a discoverability gap when delegating from a cross-repo view).

#155 must make delegation a first-class, attributed, tracked task:

• a board card (owner = "Overseer, on your behalf"; status running → done / stuck / failed) — one obvious place to see what was kicked off + where it stands;
• a unified-trace (agent_events) entry + the target session timeline entry (as today);
• the completion / stuck / needs_input result reports back visibly;
• attributed as an agent action on the user's behalf — NOT written as a chat_user turn (no faking "you" sent it).

Acceptance: after the Overseer delegates a goal, the user can see (a) that it started, (b) what the goal was, (c) its live status, and (d) the result — from a single place, without hunting through per-repo threads.

[serge-ivo]

Landed in 1a8c40d. The Overseer's delegate path now hands the GOAL to the durable Pilot (CodingSessionWorkflow objective mode) instead of a one-shot, and records an observable board task (delegationTaskRecord — type "delegation", running, attributed "Overseer delegated on your behalf", never a user turn) + a unified-trace event + a session-thread line; the Pilot flips it to completed/failed at its terminal state. Meets the acceptance criteria (see it started / the goal / live status / result from one place). delegationTaskRecord is pure + unit-tested; the goal→Pilot wiring reuses the proven /run + mirrorRuntimeTask paths. Deferred generalizations remain #156–#160.