fix: pin pydantic-ai instrumentation version

[aadetya]

📝 Summary

Closes #10238

This sets the Pydantic-AI instrumentation version to 5 so deferred frontend tool calls are not reported as tracing errors when using older supported Pydantic-AI versions.

I also updated the existing test to make sure Marimo actually passes version=5 when creating the instrumentation settings. Checking only the final value would not catch the same problem on newer Pydantic-AI versions, since they already default to version 5.

Tested with Pydantic-AI 1.107.0 and 2.9.0.

📋 Pre-Review Checklist

• This change was discussed and approved in Pydantic-AI tracing marks deferred frontend tools as errors at the supported dependency floor #10238.
• Any AI generated code has been reviewed line-by-line by the human PR author, who stands by it.
• Video or media evidence is provided for any visual changes (not applicable).

✅ Merge Checklist

• I have read the contributor guidelines.
• Documentation has been updated where applicable, including docstrings for API changes. No documentation changes were needed here.
• Tests have been added for the changes made.

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jul 21, 2026 12:25pm

[github-actions]

All contributors have signed the CLA ✍️ ✅
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[aadetya]

I have read the CLA Document and I hereby sign the CLA

[Light2Dark]

you can add a comment to this issue in the test if you want.

[aadetya]

Got it, I removed the production comment and moved the explanation to the test, where it clarifies why the explicit version=5 assertion is required.

[Light2Dark]

i'll do a small pass to improve the comment, thanks!

[github-actions]

🚀 Development release published. You may be able to view the changes at https://marimo.app?v=0.23.15-dev41