Do not merge cols when toggling from column width.

[mwynn1]

📝 Summary

Retain column metadata on cells when switching from columns width to another width type in settings

Fixes #3543

🔍 Description of Changes

Remove the mergeAllColumn call in edit-app.txt on width change.

after toggling to medium width from columns

after toggling back to columns width

📋 Checklist

• [x ] 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 13, 2025 3:02am

[github-actions]

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[mwynn1]

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[mscolnick]

this code change looks good to me (assuming it does work)

[Light2Dark]

this leads to the main view having separate sections, like in the first screenshot you took.
I think one option is in cells.ts:L1442, we don't reset the cell config's column.

        return {
          ...cells[cellId].config,
          // Preserve the original column if it exists
          column: originalColumn === undefined ? null: originalColumn
        };