✈️ Proposal for issues of 404 response for CSS files when using page caching

Description There have been ongoing issues with missing CSS files when using page caching for some time. EG: Elementor clears out CSS files on an update, and they don't get regenerated until the page gets an uncached hit, leaving many pages broken if you don't totally purge all caches, slowing down your site. I was intending to write a plugin to detect the 404 errors on css files and clear the W3 total cache of the related page, but this still has issues. The first hit to the page gets the broken styling, and the next hit gets an uncached page. In issue 27300 I saw the call to regenerate the css. So I created a proof-of-concept plugin here: It detects 404 errors for Elementor CSS files before the 404 is returned, regenerates the requested file, sends it back to the browser with a 200 header, and the file gets saved again. This way: • Full page cache doesn't need to be cleared • No one sees a broken page due to a missing css file • Elementor…