Feature/v2/selected pageeditor rework (#4756)

# Description of Changes

<!--
Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)
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---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: James Brunton <[email protected]>
Co-authored-by: Copilot <[email protected]>

frontend/src/core/components/viewer/EmbedPdfViewer.tsx

@@ -14,6 +14,7 @@ import { createStirlingFilesAndStubs } from '@app/services/fileStubHelpers';
 import NavigationWarningModal from '@app/components/shared/NavigationWarningModal';
 import { isStirlingFile } from '@app/types/fileContext';
 import { useViewerRightRailButtons } from '@app/components/viewer/useViewerRightRailButtons';
+import { useWheelZoom } from '@app/hooks/useWheelZoom';
 
 export interface EmbedPdfViewerProps {
   sidebarsVisible: boolean;
@@ -122,39 +123,11 @@ const EmbedPdfViewerContent = ({
     }
   }, [previewFile, fileWithUrl]);
 
-  // Handle scroll wheel zoom with accumulator for smooth trackpad pinch
-  useEffect(() => {
-    let accumulator = 0;
-
-    const handleWheel = (event: WheelEvent) => {
-      // Check if Ctrl (Windows/Linux) or Cmd (Mac) is pressed
-      if (event.ctrlKey || event.metaKey) {
-        event.preventDefault();
-        event.stopPropagation();
-
-        accumulator += event.deltaY;
-        const threshold = 10;
-
-        if (accumulator <= -threshold) {
-          // Accumulated scroll up - zoom in
-          zoomActions.zoomIn();
-          accumulator = 0;
-        } else if (accumulator >= threshold) {
-          // Accumulated scroll down - zoom out
-          zoomActions.zoomOut();
-          accumulator = 0;
-        }
-      }
-    };
-
-    const viewerElement = viewerRef.current;
-    if (viewerElement) {
-      viewerElement.addEventListener('wheel', handleWheel, { passive: false });
-      return () => {
-        viewerElement.removeEventListener('wheel', handleWheel);
-      };
-    }
-  }, [zoomActions]);
+  useWheelZoom({
+    ref: viewerRef,
+    onZoomIn: zoomActions.zoomIn,
+    onZoomOut: zoomActions.zoomOut,
+  });
 
   // Handle keyboard zoom shortcuts
   useEffect(() => {