Fix YouTube Briefs: Never Auto-Cancel

YouTube founder briefs (owned_youtube_brief, owned_social_youtube) must never be auto-cancelled — the founder reviews and records them on their own schedule and will signal completion manually. The current 7 briefs in the DB have stale cancelled metadata from an old sweeper run (April 23), while their DB status is still awaiting_human_approval. This inconsistency makes the must-ship panel unreliable. Additionally, _build_manual_work is called twice inside build_v4_data, adding latency and a second failure point for the must-ship panel.