Add ability to cap preview image sizes

[7w1]

Description

There wasn't a cap set for the bundled previews or incoming previews, thus you could have very large images, and the size also applied to when images failed to load, which made chats look broken. This adds a setting to cap it, defaulted to 640.

Also included a small internal fix to the new styled profiles to use code block backgrounds for the misc data instead of styled ones.

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)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• 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

AI disclosure:

• Partially AI assisted (clarify which code was AI assisted and briefly explain what it does).
• Fully AI generated (explain what all the generated code does in moderate detail).

Test updates were all fully ai generated

[github-actions]

Deploying with    Cloudflare Workers

Status	Preview URL	Commit	Alias	Updated (UTC)
✅ Deployment successful!	https://pr-783-sable.raspy-dream-bb1d.workers.dev	c372974	pr-783	Sat, 09 May 2026 21:50:07 GMT