Flatten marketing paths ahead of wiring up the websites

Drop the redundant documentation/marketing/ nesting inherited from the
plugin repos, so files sit at marketing/<plugin>/<page>.md. These paths
become raw URLs pasted into Elementor pages and ACF fields, so they are
much cheaper to change now than once sites reference them.

Fixes the four cross-plugin links for their new depth, and corrects the
README, which still pointed at the abandoned per-repo documentation/
folders instead of this repo.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

marketing/dotjuice-pagespeed/javascript-optimisation.md

@@ -0,0 +1,17 @@
+# JavaScript Optimisation
+
+Keep the browser's main thread free for what visitors actually came to see, instead of tying it up running scripts they don't need yet.
+
+## The problem it solves
+
+JavaScript is expensive in a way CSS isn't: the browser has to download it, parse it, and often execute it before it can continue rendering the page — and a lot of what loads on a typical WordPress page (analytics trackers, chat widgets, marketing pixels) has nothing to do with what a visitor sees in the first few seconds.
+
+## How it helps
+
+Dotjuice Pagespeed combines and minifies your local scripts to cut down on requests, then goes further with two complementary techniques: deferring scripts so they run after the page has rendered rather than blocking it, and — for scripts that genuinely don't need to run until a visitor interacts with the page at all — delaying them until the first scroll, click, or tap.
+
+Every exclusion is handled automatically. jQuery, Elementor's own scripts, checkout and payment processors, and any script carrying page-specific data are detected and left untouched, so the aggressive optimisations apply only where they're safe.
+
+## The result
+
+A page that's interactive sooner, because the browser isn't stuck executing a marketing pixel's JavaScript before it can respond to a click.