Add Kitty graphics protocol support

[rockorager]

Summary

Add support for the Kitty graphics protocol to enable inline image display in terminal panes.

Motivation

The Kitty graphics protocol is a widely-adopted standard for displaying images inline in terminals. Supporting it would enable:

• Inline image previews (e.g., from tools like `fzf` with image preview)
• Rich output from tools that support terminal graphics
• Better compatibility with modern terminal workflows

Implementation Notes

Since Prise uses libghostty, which has Kitty graphics support, this may involve:

• Ensuring the protocol passthrough works correctly through the multiplexer
• Handling image data in pane rendering
• Proper cleanup of graphics when panes are closed/resized

References

• Kitty Graphics Protocol Documentation