Consolidate slide preview content resolution

src/web/public/js/shared/region-content.js

@@ -0,0 +1,22 @@
+(function (root, factory) {
+  var helpers = factory();
+  if (typeof module === 'object' && module.exports) {
+    module.exports = helpers;
+  } else {
+    root.pulseRegionContent = helpers;
+  }
+})(typeof window !== 'undefined' ? window : globalThis, function () {
+  function resolveRegionContent(region, existingContent) {
+    var saved = existingContent && existingContent[region.region_key];
+    var selected = region.read_only === true || Number(region.read_only) === 1 || saved === undefined
+      ? region.default_content
+      : saved;
+    if (typeof selected === 'string') {
+      try { selected = JSON.parse(selected); } catch (_error) { selected = { value: selected }; }
+    }
+    var content = selected && typeof selected === 'object' && !Array.isArray(selected) ? selected : { value: selected };
+    return Object.assign({ type: region.region_type }, content);
+  }
+
+  return { resolveRegionContent: resolveRegionContent };
+});

src/web/public/js/slides/slide-form.js

@@ -394,14 +394,7 @@ import { createSlideAnimationEditor } from '/assets/js/slides/slide-animation-ed
       Object.assign(existingContent, savedExistingContent);
     }
     (template && Array.isArray(template.regions) ? template.regions : []).forEach(function (region) {
-      var content = region.default_content;
-      if (typeof content === 'string') {
-        try { content = JSON.parse(content); } catch (_error) { content = {}; }
-      }
-      if (!content || typeof content !== 'object' || Array.isArray(content)) content = {};
-      if (region.read_only === true || Number(region.read_only) === 1 || !Object.prototype.hasOwnProperty.call(existingContent, region.region_key)) {
-        existingContent[region.region_key] = content;
-      }
+      existingContent[region.region_key] = window.pulseRegionContent.resolveRegionContent(region, existingContent);
     });
   }