fix(web): pin dashboard sidebar and use real devinbox screenshot

[Rowee13]

Sidebar:

• Replace min-h-screen with sticky top-0 h-screen so the sidebar stays visible when the email list (or any dashboard content) scrolls past the viewport height.
• overflow-y-auto handles the edge case where the sidebar's own content exceeds viewport height.

Tool showcase:

• Swap the 1x1 placeholder PNG for the real demo-screenshot.png.
• Use intrinsic width/height with w-full h-auto so the screenshot scales proportionally without cropping or letterboxing.

Also picks up formatter drift on BrowserFrame and FeatureWishlistSection (indentation + quote style) to keep the tree clean.

Description

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test coverage improvement

Related Issues

Closes #

Changes Made

Screenshots (if applicable)

Testing

• All existing tests pass
• Added new tests for the changes
• Tested locally

Checklist

• My code follows the project's code style
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published

Additional Notes