feat: custom upload picture

[legiz-ru]

alert: created by chatgpt codex tested on my local machine (win 11)

[snakem982]

There are a few issues:

1. The page layout doesn't match the overall style.
2. The upload image button on the right seems unnecessary—clicking the text to trigger the image selection dialog would suffice.
3. The storage capacity of localStorage is limited, so large images may not be storable.

[legiz-ru]

@snakem982 updated PR

[snakem982]

The 1MB image size limit is quite restrictive. A more flexible approach would be to copy the image to the application's temporary directory—such as Pandora-Box-V3/images—and then use src-electron/server.ts to create an API that serves the image. This method is much more reasonable.