Restore image resizing in `fedify lookup` command

- Replace temporary Sharp removal with proper Jimp-based image processing
- Add support for Ghostty terminal emulator in graphics protocol detection
- Fix image output to stderr to avoid interfering with command output
- Convert images to PNG format for better terminal compatibility

This restores the image resizing functionality that was temporarily removed
in v1.8.2 due to Sharp compatibility issues with deno compile, using the
existing Jimp library that's already available in the codebase.