- Wait until the picker movie's file size stops changing before staging it, so a movie whose final bytes are still being flushed is never copied truncated (which produced drafts without a thumbnail and unplayable previews). - Log the whole camera video path (pickup size, staging result, analyze outcome, thumbnail decode) under the video-preview os_log category for fast on-device diagnosis. - Cover the video analysis pipeline with a simulator test that generates an HEVC QuickTime movie and asserts duration plus JPEG thumbnail, and guard the diagnostics in Scripts/verify.sh.