When checkpoints and unet folders point to the same physical location
(via symlinks), prioritize checkpoints for backward compatibility.
This prevents the 'Failed to load Checkpoint root' error that users
experience when they have incorrectly configured their ComfyUI paths.
Changes:
- Detect overlapping real paths between checkpoints and unet
- Log warning to inform users of the configuration issue
- Remove overlapping paths from unet_map, keeping checkpoints
Fixes #<issue-number>
