#8821 docs(library): update open-source-ai-agent-platforms

Summary

• Refreshes the library post open-source-ai-agent-platforms (apps/sim/content/library/open-source-ai-agent-platforms/index.mdx).
• Title unchanged.
• A replacement article was merged into the existing post.
• Requested change: MERGE this refresh into the existing library/open-source-ai-agent-platforms post; do not replace or swap the existing article wholesale. Preserve every existing FAQ question verbatim unless a first-party source proves its premise false, every H2 and H3, every product currently compared, every outbou…

Generated by the Library Post PR Updater workflow. Not built or tested locally. After the PR opens, the workflow content gate checks changed paths, frontmatter keys, FAQ placement, and internal links; CI check:library-content validates the post once it is enabled.

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