Update docs; resolve #6623

[stephenlf]

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📝 Summary

Clarified guide page "Run as an app" to resolve #6623

Description

• Moved note about layouts/ folder from ### Grid layout to ## Layout, since it applies to both Grid and Slides layouts.
• Added instruction to include layouts/ folder in version control.

📋 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	Preview	Comments	Updated (UTC)
marimo-docs	Ready	Preview	Comment	Oct 6, 2025 2:35pm

[github-actions]

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[stephenlf]

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