fix(skills): omit column widths by default in generated grid code

[onlyexeption]

Closes #1696

Description

Provide a clear and concise summary of the changes in this PR and the motivation behind them

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that causes existing functionality to change)
• Documentation update
• Refactoring (code improvements without functional changes)

Related Issues

Closes #

Testing

Checklist

• My code follows the project's coding standards
• I have tested my changes locally
• I have updated documentation if needed
• Breaking changes are documented in the description

[Copilot]

Pull request overview

This PR appears intended to address #1696 by ensuring generated grid code does not include column width by default, but the current diff only updates the “gotchas” reference documentation for the image-to-design generation skill.

Changes:

• Added a new “gotcha” section advising omitting column width for Grid Lite and Advanced Grid to keep columns fluid by default.
• Documented a narrow exception note about resizable Grid Lite columns using px.