Changes:
- folder_mode=True: Always use folder_path for random selection
- folder_mode=False: Always use file picker (image_data)
- Auto-switch: File picker automatically sets folder_mode=False
Behavior:
- User clicks 📁 Choose File → auto-switches to Single mode
- folder_mode toggle explicitly controls which input to use
- No more auto-detection ambiguity
- Clear separation between modes
Benefits:
- Predictable behavior based on folder_mode setting
- File picker prioritized by auto-switching to Single mode
- User can maintain folder_path while using file picker
- Cleaner error messages for each mode
solidlime
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