display reasoning, tools in ui.chat

[Light2Dark]

📝 Summary

• Adds display for tools, reasoning, file attachments (standardized)
• Fixes chatConfig in the UI. Eg. Claude reasoning models don't allow you to pass in top_p and temperature. So we should allow nulls.
• Minor style fixes for the chatbot, buttons are too prominent.

Screen.Recording.2026-01-01.at.3.14.09.AM.mov

🔍 Description of Changes

📋 Checklist

• I have read the contributor guidelines.
• For large changes, or changes that affect the public API: this change was discussed or approved through an issue, on Discord, or the community discussions (Please provide a link if applicable).
• I have added tests for the changes made.
• I have run the code and verified that it works as expected.

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Project	Deployment	Review	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jan 4, 2026 11:30am