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/package-lock.json

@@ -10,6 +10,7 @@
       "license": "SEE LICENSE IN https://raw.githubusercontent.com/Stirling-Tools/Stirling-PDF/refs/heads/main/proprietary/LICENSE",
       "dependencies": {
         "@atlaskit/pragmatic-drag-and-drop": "^1.7.7",
+        "@dnd-kit/core": "^6.3.1",
         "@embedpdf/core": "^1.4.1",
         "@embedpdf/engines": "^1.4.1",
         "@embedpdf/plugin-annotation": "^1.4.1",
@@ -505,6 +506,63 @@
         "node": ">=18"
       }
     },
+    "node_modules/@dnd-kit/accessibility": {
+      "version": "3.1.1",
+      "resolved": "https://registry.npmjs.org/@dnd-kit/accessibility/-/accessibility-3.1.1.tgz",
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+      "license": "MIT",
+      "dependencies": {
+        "tslib": "^2.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=16.8.0"
+      }
+    },
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+      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.8.1.tgz",
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+      "license": "0BSD"
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+    "node_modules/@dnd-kit/core": {
+      "version": "6.3.1",
+      "resolved": "https://registry.npmjs.org/@dnd-kit/core/-/core-6.3.1.tgz",
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+      "license": "MIT",
+      "dependencies": {
+        "@dnd-kit/accessibility": "^3.1.1",
+        "@dnd-kit/utilities": "^3.2.2",
+        "tslib": "^2.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=16.8.0",
+        "react-dom": ">=16.8.0"
+      }
+    },
+    "node_modules/@dnd-kit/core/node_modules/tslib": {
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+      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.8.1.tgz",
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+      "license": "0BSD"
+    },
+    "node_modules/@dnd-kit/utilities": {
+      "version": "3.2.2",
+      "resolved": "https://registry.npmjs.org/@dnd-kit/utilities/-/utilities-3.2.2.tgz",
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+      "license": "MIT",
+      "dependencies": {
+        "tslib": "^2.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=16.8.0"
+      }
+    },
+    "node_modules/@dnd-kit/utilities/node_modules/tslib": {
+      "version": "2.8.1",
+      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.8.1.tgz",
+      "integrity": "sha512-oJFu94HQb+KVduSUQL7wnpmqnfmLsOA/nAh6b6EH0wCEoK0/mPeXU6c3wKDV83MkOuHPRHtSXKKU99IBazS/2w==",
+      "license": "0BSD"
+    },
     "node_modules/@embedpdf/core": {
       "version": "1.4.1",
       "resolved": "https://registry.npmjs.org/@embedpdf/core/-/core-1.4.1.tgz",