Improve copying image to clipboard

[birdddev]

• Use Electron's api to do the operation instead of the Browser's
• No longer needlessly converting buffers, so should be way faster
• Will always work, even if the window becomes un-focused
• New toast for displaying the copied image

This may be a bit sloppy.

[rvion]

looks good ! 🔥👍

[rvion]

🔥 Great PR, thanks !