[V2] refactor(ui): migrate compress/booklet/sign-up to Mantine Checkbox (#4886)

# Description of Changes
- Updated `BookletImpositionSettings` to use Mantine's `Checkbox` for
better UI consistency
- Replaced manual checkbox implementations with Mantine's `Checkbox` in
`CompressSettings`
- Added labels and tooltips for enhanced accessibility and usability

### Before:

<img width="225" height="347" alt="image"
src="https://github.com/user-attachments/assets/2bc2e5bd-33e8-40c3-8957-8ed461f7f397"
/>
<img width="225" height="347" alt="image"
src="https://github.com/user-attachments/assets/04425759-f05d-4a41-829e-30cc8febcc59"
/>
<img width="225" height="347" alt="image"
src="https://github.com/user-attachments/assets/a25122ab-377b-48a0-9692-7548e4cb2100"
/>
<img width="225" height="347" alt="image"
src="https://github.com/user-attachments/assets/bb206b71-9252-4bba-8627-d211de21d404"
/>



### After:

<img width="225" height="347" alt="image"
src="https://github.com/user-attachments/assets/3d797372-a97b-4a6b-94f7-8478cea3776e"
/>
<img width="225" height="347" alt="image"
src="https://github.com/user-attachments/assets/310bbc9b-60e7-4e00-b8f2-e2290d20b307"
/>

<img width="225" height="397" alt="image"
src="https://github.com/user-attachments/assets/207f9b1d-5f2d-4c67-a97d-74dece3adef7"
/>
<img width="225" height="397" alt="image"
src="https://github.com/user-attachments/assets/ee3889eb-5494-4763-993e-76dbd0aa4c26"
/>

<!--
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)

### 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)

- [ ] 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/src/proprietary/routes/signup/SignupForm.tsx

@@ -1,6 +1,7 @@
 import { useEffect } from 'react';
 import '@app/routes/authShared/auth.css';
 import { useTranslation } from 'react-i18next';
+import { Checkbox } from '@mantine/core';
 import { SignupFieldErrors } from '@app/routes/signup/SignupFormValidation';
 
 interface SignupFormProps {
@@ -133,19 +134,20 @@ export default function SignupForm({
       {/* Terms - only show if showTerms is true */}
       {showTerms && (
         <div className="auth-terms">
-          <input
+          <Checkbox
             id="agree"
-            type="checkbox"
             checked={agree}
-            onChange={(e) => setAgree?.(e.target.checked)}
+            onChange={(e) => setAgree?.(e.currentTarget.checked)}
             className="auth-checkbox"
+            label={
+              <span className="auth-terms-label">
+                {t("legal.iAgreeToThe", 'I agree to all of the')}{' '}
+                <a href="https://www.stirlingpdf.com/terms" target="_blank" rel="noopener noreferrer">
+                  {t('legal.terms', 'Terms and Conditions')}
+                </a>
+              </span>
+            }
           />
-          <label htmlFor="agree" className="auth-terms-label">
-            {t("legal.iAgreeToThe", 'I agree to all of the')} {" "}
-            <a href="https://www.stirlingpdf.com/terms" target="_blank" rel="noopener noreferrer">
-              {t('legal.terms', 'Terms and Conditions')}
-            </a>
-          </label>
         </div>
       )}