[chuks-qua]

What

Before this change, a Coordinator whose turn had ended looked idle even while a task it started with delegate_task was still running. The child thread is hidden from the sidebar, so nothing on screen said work was still going on.

Now the Coordinator's sidebar row shows the normal running mark while any of its delegated tasks is unfinished. The open conversation keeps its status line, reading "Waiting on subagents" with the layers icon. It shows no step count and no clock, because those belong to the turn that already ended. Both clear when the last task finishes, fails, or is stopped, and the status line fades out in the same shape.

 ThreadAttention (thread.attention, broadcast to every client)
   threadId, waiting, lastTurn, seen
+  hasUnfinishedDelegatedTasks   # derived on read, never stored

server
  DelegatedTaskStore.listUnfinishedCandidates   # SQL drops tasks with durable terminal evidence
  DelegatedTaskService.coordinatorsWithUnfinishedTasks
    deriveTaskState(turn, startup, approval, launching)   # same rule task_status uses
  invalidate Coordinator attention on
    roster change, launch start, settled child turn
web
  deriveThreadRowState
    needs-you  >  own running  >  plan ready  >  unseen Interrupted
      >  delegating -> running  >  unseen Failed/Finished  >  quiet
  narrativeIndicatorItem
    own turn idle + delegating -> "Waiting on subagents", no steps, no clock

Verified with the targeted suites (67 server tests, 225 web tests), the contracts, server, and web typechecks, lint, and live captures in Electron.

Why

Users hand long work to delegated tasks and then look away. If the Coordinator reads as idle, they can't tell whether the work is still going or forgotten without opening the task. Closes #2266.

UI Changes

Captured live in Electron. A Claude Coordinator delegates a two-minute shell task with delegate_task and ends its own turn.

Before (main)	After

When the task finishes, both clear:

Review Notes

• Wire schema. ThreadAttentionSchema is strict, like every wire schema here. A web tab still running a pre-change bundle drops attention pushes until it reloads. The desktop app ships client and server together, so it is not affected.
• Toast timing. The turn-end toast now waits until the last delegated task ends, because a running row defers toast accounting. This is deliberate. A task-finished toast is out of scope (feat: wake the Coordinator thread when a delegated task finishes #2217 wakes the Coordinator instead).
• Stop button. The composer stop button still follows the Coordinator's own turn only. Stopping a delegated task stays in its chip.
• Abandoned tasks. A task whose startup is left pending or blocked, or whose approval stays pending, keeps the Coordinator running. This matches what task_status reports for the same task.
• No migration and no cache. The flag is derived on each attention read from one prefilter query joined on primary keys plus per-task lifecycle reads.
• Documentation: none needed. The behavior follows the existing running indicators.

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