Track outbound clicks as Plausible custom events

js/plausible-events.js classifies every outbound click:
  Affiliate Click  — host in AFFILIATES map, or rel=sponsored
  Outbound Click   — any other external link
props: network, destination, destination_path, placement (utm_medium),
link_text, lang. Internal links, in-page anchors, mailto: and tel: are ignored;
data-plausible-skip opts an element out. Adding a new partner is one line in
AFFILIATES. Loaded on 1206 pages before </body>.

Create the two goals in Plausible (Settings -> Goals -> Custom event) named
exactly 'Affiliate Click' and 'Outbound Click' for them to show as conversions.

add-performance.html

@@ -180,5 +180,6 @@ app.use(compression());
     </div>
     <p>This will add gzip compression, reducing transfer sizes by ~70% for text files.</p>
 
+    <script src="/js/plausible-events.js" defer></script>
 </body>
 </html>