[V2] refactor(ui): replace native inputs with Mantine components (#4898)

# Description of Changes

#### Before
<img width="779" height="768" alt="image"
src="https://github.com/user-attachments/assets/a6d63bac-e27d-4bd8-b44e-fa72333f4c59"
/>


#### After
<img width="779" height="768" alt="image"
src="https://github.com/user-attachments/assets/f39d8d92-802a-40ff-a7db-2b6a187b6847"
/>


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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)

### 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]>
Co-authored-by: Reece Browne <[email protected]>

frontend/src/core/components/shared/sliderWithInput/SliderWithInput.tsx

@@ -8,6 +8,7 @@ interface Props {
   min?: number;
   max?: number;
   step?: number;
+  suffix?: string;
 }
 
 export default function SliderWithInput({
@@ -18,11 +19,12 @@ export default function SliderWithInput({
   min = 0,
   max = 200,
   step = 1,
+  suffix = '%',
 }: Props) {
   return (
     <div>
-      <Text size="sm" fw={600} mb={4}>{label}: {Math.round(value)}%</Text>
-      <Group gap="sm" align="center">
+      <Text size="sm" fw={500} mb={8}>{label}</Text>
+      <Group gap="md" align="center">
         <div style={{ flex: 1 }}>
           <Slider min={min} max={max} step={step} value={value} onChange={onChange} disabled={disabled} />
         </div>
@@ -33,6 +35,7 @@ export default function SliderWithInput({
           max={max}
           step={step}
           disabled={disabled}
+          suffix={suffix}
           style={{ width: 90 }}
         />
       </Group>