/new-task (and every intake: GitHub issue, /sh-assign-task) reached the clarifier
with NO description -> the clarifier asked 'no task description provided'. Root
cause: coordinator.start_task only LOGGED task_text (a P1-era decision when the
deterministic clarifier didn't consume a description), graph.start_task took no
task arg, and PipelineState/TaskRecord had no 'task' channel at all.
Fix: add a first-class 'task' field to PipelineState + TaskRecord (+ round-trip
in task_from_dict); graph.start_task seeds task into the initial invoke (persists
through intake_node's partial-state return into CLARIFY); coordinator.start_task
passes task=task_text. The clarifier already reads state['task'] via
_task_description, so it now sees the real description.
Test: start_task(task='build a login form') -> suspended CLARIFY state carries
task. 1143 passed, ruff clean.
