enhancement: update thumbnail chat width option setting

[urmauur]

Describe Your Changes

1. Image Updates and Additions:

   • New image files compact-width-dark.png and full-width-dark.png are added to web/public/images/.
   • Existing images compact-width.png and full-width.png have been modified.

2. Component Updates in index.tsx:

   • A new import for twMerge from tailwind-merge to handle Tailwind CSS class merging has been added.
   • The useTheme hook now also retrieves the theme variable, in addition to setTheme.
   • The chatWidthOption array is updated to include darkImg properties for each width option.
   • The src attribute of the <img> tag is now conditionally set based on the theme: it uses option.darkImg if the theme is 'dark', and option.img otherwise.
   • The <label> no longer contains a radio <input>. Instead, it directly triggers the setChatWidth(option.value) action using an onClick event.
   • Additional SVG rendering logic has been added to visually indicate the selected chat width, showing a checkmark icon when an option is selected.

These changes suggest updates to improve the theming capabilities of an application, specifically around handling light and dark themes more gracefully in the appearance settings UI.

Fixes Issues

• Closes feat: Add Chat Width settings option for Threads #3509
• Closes #

Self Checklist

• Added relevant comments, esp in complex areas
• Updated docs (for bug fixes / features)
• Created issues for follow-up changes or refactoring needed
  

[github-actions]

Barecheck - Code coverage report

Total: 69.1%

Your code coverage diff: 0.00% ▴

✅ All code changes are covered

[github-actions]

This is the build for this pull request. You can download it from the Artifacts section here: Build URL.