[V2] refactor(tooltips): add merge tooltips header for consistency, and update other tooltips (#4895)

# Description of Changes

Note on tooltips: I'll do more PRs on tooltips, however this has
priority, hence I submitted this for now.


#### Before:

<img width="758" height="721" alt="image"
src="https://github.com/user-attachments/assets/ce3166d2-c681-447e-82df-68fe6d18669d"
/>

<img width="782" height="485" alt="image"
src="https://github.com/user-attachments/assets/48970a4c-9911-4ade-9346-c33c5a6a319f"
/>

<img width="782" height="602" alt="image"
src="https://github.com/user-attachments/assets/9f77648d-4d1a-4e4b-93af-eaab6db849ff"
/>

<img width="782" height="602" alt="image"
src="https://github.com/user-attachments/assets/ae653534-bf04-47a0-8aab-0bb5b9c3ecef"
/>

#### After:
<img width="758" height="721" alt="image"
src="https://github.com/user-attachments/assets/8d45e876-a0df-4fe3-89a8-5184492db204"
/>

<img width="782" height="602" alt="image"
src="https://github.com/user-attachments/assets/550ee105-1286-4072-9f55-46255b3fbe80"
/>

<img width="782" height="602" alt="image"
src="https://github.com/user-attachments/assets/fba7ea93-73fe-4529-84fe-c37816375a9e"
/>
<img width="782" height="602" alt="image"
src="https://github.com/user-attachments/assets/ca452e77-b58b-4a5b-8e97-e6ccef4cf500"
/>


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

Closes #(issue_number)
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---

## Checklist

### General

- [X] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [X] 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)
- [X] I have performed a self-review of my own code
- [X] 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)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [X] 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.

---------

Signed-off-by: Balázs Szücs <[email protected]>

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

@@ -918,6 +918,11 @@
     },
     "error": {
       "failed": "An error occurred while merging the PDFs."
+    },
+    "tooltip": {
+      "header": {
+        "title": "Merge Settings Overview"
+      }
     }
   },
   "split": {
@@ -2372,6 +2377,14 @@
       "title": "About Remove Annotations",
       "description": "This tool will remove all annotations (comments, highlights, notes, etc.) from your PDF documents."
     },
+    "tooltip": {
+      "header": {
+        "title": "About Remove Annotations"
+      },
+      "description": {
+        "title": "What it does"
+      }
+    },
     "error": {
       "failed": "An error occurred while removing annotations from the PDF."
     }
@@ -2834,6 +2847,9 @@
       "header": {
         "title": "How Auto-Rename Works"
       },
+      "description": {
+        "title": "What it does"
+      },
       "howItWorks": {
         "title": "Smart Renaming",
         "text": "Automatically finds the title from your PDF content and uses it as the filename.",
@@ -2841,6 +2857,9 @@
         "bullet2": "Creates a clean, valid filename from the detected title",
         "bullet3": "Keeps the original name if no suitable title is found"
       }
+    },
+    "settings": {
+      "title": "About"
     }
   },
   "adjust-contrast": {
@@ -4934,6 +4953,14 @@
     "addMoreFiles": "Add more files...",
     "selectedFiles": "Selected Files",
     "submit": "Add Attachments",
+    "tooltip": {
+      "header": {
+        "title": "About Add Attachments"
+      },
+      "description": {
+        "title": "What it does"
+      }
+    },
     "results": {
       "title": "Attachment Results"
     },