Schedule tasks can't choose provider / model / reasoning effort

[wycx886]

schedule_create and schedule_edit accept title, prompt, rrule, target — but no model. When a new_once / new task creates its Session, createAgent() calls controller.create({ sessionId, cwd?, agentPreset? }) (dsh-schedule/lib/index.js), so no selection is passed and the Session runs on the Host default (agent-default-model). The Automation tasks page has no model control either, and schedule_list / schedule_view don't report one, so there is no way to see or change what a task will run on. A this_session task does inherit its conversation's model; the gap is exactly where Schedule creates the Session.

That matters most for unattended work: a 15-minute heartbeat should run on a cheap fast model, a weekly report on a strong one at high effort, and a provider incident should be routable per task rather than by changing the global default for every session.

Ask. Optional provider, model, and reasoningEffort on schedule_create / schedule_edit, persisted with the task and applied to the Session it creates. Omitted fields keep today's behavior; the resolved choice shows on the task card and in schedule_list / schedule_view; the pair is validated at arming time. Additive and opt-in — nothing changes for tasks that omit them.

Prior art. #3831 asked for this and moved to titanwings/dsh-automation#9 while automation was a plugin; v0.1.7 implemented it (pin a provider/model + effort, or follow the live global selection). #8167's fresh-session delivery shipped — model choice is the other half, and Schedule is first-party now.

Reproduction. Default model A, conversation switched to B, schedule_create with target: new_once → the delivered conversation starts on A.