Start a task recording

Creates a version-3 task preparation ready for recording without a title, description, or initial model call. Optional supplied wording is retained. Each member can have one unfinished new-task draft. A second start returns 409 with its recovery link; list with state=draft to resume, or explicitly discard the draft before starting another. Drafts survive closing, navigation, and processing failures until published or cancelled. Published-task revisions remain independent. Use the private recording link by default, or add a completed external screen recording through evidence with recordingMode set to screen. Every unpublished task requires a screen walkthrough with meaningful narration; supplied text and Context supplement it. The owner can explicitly accept an inconclusive content check for its current fingerprint through accept-recording. Explicitly call analyze to validate the recording, freeze Context, and begin understanding. Final approval and publication are separate operations.