[Feature Request] Configurable and Toggleable Mail Analysis Functionality

[flyingswan3000]

Suggestions for improving the mail analysis feature:

1. Allow customization of html-validate settings in appsettings.json. Current rules aren't always suitable for email HTML.

2. Add option to disable HTML validation. Large HTML emails generate many warnings, severely impacting UI performance. Example: 7000+ warnings caused 3-minute browser freeze.

3. Implement pagination for HTML validation results to better manage large numbers of warnings.

These changes would enhance flexibility and performance, especially for complex HTML emails.

[rnwood]

Thanks for the feedback on this.

For 1. it would be nice to get a more appropriate default rule set in addition to allowing it to be customised. Can you comment on any specific rules you think aren't appropriate?

[rnwood]

It would be great to also move the analysis into a background worker, so even when it's on, it doesn't block the UI.