Feature/v2/right rail (#4255)

# Description of Changes

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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: ConnorYoh <[email protected]>
Co-authored-by: Anthony Stirling <[email protected]>

frontend/public/locales/en-GB/translation.json

@@ -992,6 +992,7 @@
     },
     "submit": "Change"
   },
+  
   "removePages": {
     "tags": "Remove pages,delete pages",
     "title": "Remove Pages",
@@ -1926,6 +1927,19 @@
     "currentPage": "Current Page",
     "totalPages": "Total Pages"
   },
+  "rightRail": {
+    "closeSelected": "Close Selected Files",
+    "selectAll": "Select All",
+    "deselectAll": "Deselect All",
+    "selectByNumber": "Select by Page Numbers",
+    "deleteSelected": "Delete Selected Pages",
+    "closePdf": "Close PDF",
+    "exportAll": "Export PDF",
+    "downloadSelected": "Download Selected Files",
+    "downloadAll": "Download All",
+    "toggleTheme": "Toggle Theme",
+    "language": "Language"
+  },
   "toolPicker": {
     "searchPlaceholder": "Search tools...",
     "noToolsFound": "No tools found",