- Added generate_thumbnail_prompt(notes) to thumbnail_utils.py
- yt_poster.py now reads notes.txt (if present) from the clip directory
- Uses content to generate brand-aligned OpenAI prompt for future AI thumbnail generation
- Fallback: generic description if notes.txt is missing
- Prompt is printed for now; image generation hook is pending
- Moved generate_thumbnail() and thumbnails().set() to run after video upload
- Now waits for video_id before attempting thumbnail upload
- Applies only to widescreen videos (Shorts still skip thumbnails)
- Integrated generate_thumbnail() into upload_video()
- Attempted to upload custom thumbnail via thumbnails().set()
- Applies only to widescreen videos (not vertical Shorts)
- NOTE: Bug present — tries to upload thumbnail before video_id is available
- Will fix by reordering after upload in next commit
