Two gaps surfaced by a live /new-task (task 9bce78ad): the plan was produced
and approved, but the "plan ready" notice posted top-level (not in the task
thread) and contained no plan to review.
1. THREADING — `run-team.py` `_build_notifiers` exposed `notify(message)` with
no `thread_ts`. The coordinator's `_emit` calls `notify(message,
thread_ts=root)`; that raised TypeError, and `_emit`'s fallback re-posted
TOP-LEVEL. So every lifecycle milestone (plan-ready / parked / failed) landed
unthreaded, despite the coordinator computing the root ts. (The clarifier
QUESTION threaded fine — different path.) Fix: the sink now accepts and
forwards `thread_ts` into the chat.postMessage payload (build_slack_poster
already forwards the key).
2. PRESENTATION — the plan-ready milestone was a bare one-liner. It now posts a
CONDENSED plan (summary + numbered phase names; step detail stays on the
status dashboard) via new `Coordinator._summarize_plan`, so the plan is
actually reviewable in-thread.
Tests: notify sink forwards thread_ts (and omits it for top-level); condensed
plan renders summary + phase names (not steps); malformed plan falls back;
plan-ready milestone threads under the task root AND carries the plan. 1193 pass.
