A `Workflow` tool-use launches its multi-agent run in the background and
returns immediately; the real fan-out arrives out-of-band on stream-json
`type:"system"` task_* events (task_started / task_progress / task_updated /
task_notification) keyed by the launching tool-use id — which clide was
dropping. (Wire shape captured by two live stream-json probes; recorded on
the ticket.)
- workflow_run.dart: a pure, Flutter-free WorkflowRun/WorkflowAgent model
that folds those events (phases, per-agent start→progress→done deltas,
usage) into a snapshot.
- StreamJsonSession recognises the events, accumulates a
Map<toolUseId, WorkflowRun>, and exposes `workflows` + `workflowsStream`.
- A `Workflow` tool-use with a live run renders a dedicated run card —
phase groups, per-agent rows with spinner/check status, usage, and the
script — falling back to the generic tool card pre-progress or on reload.
The run breaks the activity cluster so it's always first-class (like T-342).
- The sidebar Activity tab adds a WORKFLOWS section: one row per run with its
done/total agent count, tinted by running/done state.
Closes T-416 and the T-410 epic (all children done).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>