feat: Add new Affinity namespace

(complements the legacy Serif namespace previously added in 5d97108)

Author: tomalakgeretkal

plugins/_collections.js

@@ -2102,6 +2102,7 @@ export const editorNamespaces = new Set([
   'http://www.vector.evaxdesign.sk',
   'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
   'https://boxy-svg.com',
+  'https://www.affinity.studio/',
 ]);
 
 /**