For the technologies/standards (CORS, websockets, cookies, etc.) I'd recommend reading the wikipedia article and then the relevant RFC/standard (which will surely be linked from wikipedia).
The server side things you mentioned (sessions, rendering, etc) are functionalities/techniques/patterns that different frameworks implement in different ways, so I'm not sure there's much material that talk about them in general (or much to say about them in general)... you'll probably have to explore them in deep with your framework/s of choice (ie. looking at how the framework implements that functionality rather than just using it).