feature: add high-res image preview modal to prompt box
- Added click-to-preview functionality for reference and end frame
images in `ImagePromptRow`.
- Updated `RefImage` interface to include `fullUrl` for fetching
high-resolution library images.
- Populated `fullUrl` for library selections in `create-image` and
`create-video` pages.
- Configured the preview modal to tightly wrap the image so the close
button anchors correctly to the corner.
- Updated the image uploading indicator to use the standardized
`spinner-third` icon.
Tanish Mankuandbflatastic