[FEATURE] Dispatch: choose model and effort for the sessions and tasks it creates

Problem
When I send a task through Dispatch (Claude mobile app / claude.ai) and it starts a Code session on my Mac's desktop app, I can't choose the model or reasoning effort. My session started on Opus 4.8 when I wanted Opus 5.5. The only fix was running /model inside the session after it had already started. The docs don't say how Dispatch picks a model, or whether it reads model / effortLevel from ~/.claude/settings.json.

Request

1. A model and effort picker when sending a task through Dispatch, and for any new sessions or tasks Dispatch creates.
2. A default that sticks: Dispatch should respect model and effortLevel in user settings, or have its own default setting.
3. Docs on which setting wins for Dispatch-started sessions.

Related: #94889 (the same picker for Agent view), #49649 (switching models on Cowork tasks)

Environment: Claude desktop app, Code tab, macOS 27; the session reported that a remote orchestrator started it.