fix(track-changes): allow linked style changes in suggesting mode (SD-2182)

Heading/paragraph style changes were silently blocked in suggesting mode.
tr.setNodeMarkup() produces a ReplaceAroundStep which was being dropped
by the track changes handler. This detects node markup changes (same
structure, different attrs) and allows them through. Also removes the
empty selection guard from toggleLinkedStyle so keyboard shortcuts work.

Note: style changes are applied directly without tracked change marks.
Tracked change decoration for paragraph styles is a follow-up.

Author: caio-pizzol

packages/super-editor/src/extensions/linked-styles/linked-styles.js

@@ -61,14 +61,11 @@ export const LinkedStyles = Extension.create({
        * @example
        * const style = editor.helpers.linkedStyles.getStyleById('Heading1');
        * editor.commands.toggleLinkedStyle(style)
-       * @note If selection is empty, returns false
+       * @note Works with both cursor position and text selection
        * @note Removes style if already applied, applies it if not
        */
       toggleLinkedStyle: (style) => (params) => {
         const { tr } = params;
-        if (tr.selection.empty) {
-          return false;
-        }
         let node = tr.doc.nodeAt(tr.selection.$from.pos);
 
         if (node && node.type.name !== 'paragraph') {

packages/super-editor/src/extensions/track-changes/trackChangesHelpers/replaceAroundStep.js

@@ -94,6 +94,16 @@ export const replaceAroundStep = ({
     return;
   }
 
+  // Detect setNodeMarkup steps: they preserve the node type and content,
+  // only changing attributes (e.g. paragraph styleId for heading changes).
+  // These are safe to apply — they don't alter document structure.
+  const isNodeMarkupChange = step.structure && step.gapFrom === step.from + 1 && step.gapTo === step.to - 1;
+
+  if (isNodeMarkupChange) {
+    newTr.step(step);
+    return;
+  }
+
   const inputType = tr.getMeta('inputType');
   const isBackspace = inputType === 'deleteContentBackward';