Interop blog polishing

[rjambrecic]

Why are these changes needed?

main branch currently contains only the initial iteroperability blog post.

• Update content
• Add references to the API documentation
• Add placeholder to YouTube video

Related issue number

Checks

• I've included any doc changes needed for https://ag2ai.github.io/ag2/. See https://ag2ai.github.io/ag2/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.