I totally agree with you regarding learning about grids and responsive design. In fact, any designer who works on web apps and doesn’t know how pages are put together and can’t look in the browser dev tools should find a different job.

I also agree on early design “tire kicking” to field questions from developers.

However, I disagree on trying to annotate everything vs asking a developer to use the code inspect tool in Figma, for example. I used to redline everything back in the day and developers complained there were too many notes and specs next to the designs. Figma and similar tools are built to provide inspectable, copy-able code snippets (css, hex codes, etc). Please, developers, meet designers halfway; don't expect them to do all the work.