V2 flatten (#4358)

# 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: James Brunton <[email protected]>
Co-authored-by: ConnorYoh <[email protected]>

frontend/src/components/tools/flatten/FlattenSettings.tsx

@@ -0,0 +1,35 @@
+import { Stack, Text, Checkbox } from "@mantine/core";
+import { useTranslation } from "react-i18next";
+import { FlattenParameters } from "../../../hooks/tools/flatten/useFlattenParameters";
+
+interface FlattenSettingsProps {
+  parameters: FlattenParameters;
+  onParameterChange: <K extends keyof FlattenParameters>(key: K, value: FlattenParameters[K]) => void;
+  disabled?: boolean;
+}
+
+const FlattenSettings = ({ parameters, onParameterChange, disabled = false }: FlattenSettingsProps) => {
+  const { t } = useTranslation();
+
+  return (
+    <Stack gap="md">
+      <Stack gap="sm">
+        <Checkbox
+          checked={parameters.flattenOnlyForms}
+          onChange={(event) => onParameterChange('flattenOnlyForms', event.currentTarget.checked)}
+          disabled={disabled}
+          label={
+            <div>
+              <Text size="sm">{t('flatten.options.flattenOnlyForms', 'Flatten only forms')}</Text>
+              <Text size="xs" c="dimmed">
+                {t('flatten.options.flattenOnlyForms.desc', 'Only flatten form fields, leaving other interactive elements intact')}
+              </Text>
+            </div>
+          }
+        />
+      </Stack>
+    </Stack>
+  );
+};
+
+export default FlattenSettings;