Fix CLI JSON output regression in lookup command

The -r/--raw, -C/--compact, and -e/--expand options were incorrectly
outputting Deno's object inspection format instead of valid JSON.

This commit:

- Consolidates formatting logic into a single formatObject() function
- Adds proper JSON stringification for JSON output modes
- Maintains Deno.inspect() for non-JSON display modes
- Preserves syntax highlighting for colored JSON output

Fixes https://github.com/fedify-dev/fedify/issues/357