fix(certSign): accept .pfx/.p12 uploads for PKCS12 and ensure PFX files are included in form data (#5391)

# Description of Changes

This pull request improves the handling of PKCS12 and PFX certificate
file types in the certificate signing tool. The main changes unify and
simplify the logic for uploading and processing these file types,
ensuring consistent behavior and reducing code duplication.

**Certificate file upload improvements:**

* Updated the `CertificateFilesSettings` component to handle both
`PKCS12` and `PFX` certificate types in a single file upload input,
allowing selection of either `.p12` or `.pfx` files and dynamically
adjusting the placeholder text.

**Certificate signing logic updates:**

* Modified the `buildCertSignFormData` function to append the uploaded
file for both `PKCS12` and `PFX` certificate types, ensuring both are
supported during form data construction.

<img width="1916" height="463" alt="image"
src="https://github.com/user-attachments/assets/51dbe130-c25b-4b77-aecd-f3d55d5c62ae"
/>


---

## 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.

frontend/src/core/components/tools/certSign/CertificateFilesSettings.tsx

@@ -36,23 +36,17 @@ const CertificateFilesSettings = ({ parameters, onParameterChange, disabled = fa
         </Stack>
       )}
 
-      {parameters.certType === 'PKCS12' && (
+      {(parameters.certType === 'PKCS12' || parameters.certType === 'PFX') && (
         <FileUploadButton
           file={parameters.p12File}
           onChange={(file) => onParameterChange('p12File', file || undefined)}
-          accept=".p12"
+          accept=".p12,.pfx"
           disabled={disabled}
-          placeholder={t('certSign.chooseP12File', 'Choose PKCS12 File')}
-        />
-      )}
-
-      {parameters.certType === 'PFX' && (
-        <FileUploadButton
-          file={parameters.p12File}
-          onChange={(file) => onParameterChange('p12File', file || undefined)}
-          accept=".pfx"
-          disabled={disabled}
-          placeholder={t('certSign.choosePfxFile', 'Choose PFX File')}
+          placeholder={
+            parameters.certType === 'PFX'
+              ? t('certSign.choosePfxFile', 'Choose PFX File')
+              : t('certSign.chooseP12File', 'Choose PKCS12 File')
+          }
         />
       )}
 
@@ -92,4 +86,4 @@ const CertificateFilesSettings = ({ parameters, onParameterChange, disabled = fa
   );
 };
 
-export default CertificateFilesSettings;
+export default CertificateFilesSettings;

frontend/src/core/hooks/tools/certSign/useCertSignOperation.ts

@@ -7,14 +7,14 @@ import { CertSignParameters, defaultParameters } from '@app/hooks/tools/certSign
 export const buildCertSignFormData = (parameters: CertSignParameters, file: File): FormData => {
   const formData = new FormData();
   formData.append('fileInput', file);
-  
+
   // Handle sign mode
   if (parameters.signMode === 'AUTO') {
     formData.append('certType', 'SERVER');
   } else {
     formData.append('certType', parameters.certType);
     formData.append('password', parameters.password);
-    
+
     // Add certificate files based on type (only for manual mode)
     switch (parameters.certType) {
       case 'PEM':
@@ -26,6 +26,7 @@ export const buildCertSignFormData = (parameters: CertSignParameters, file: File
         }
         break;
       case 'PKCS12':
+      case 'PFX':
         if (parameters.p12File) {
           formData.append('p12File', parameters.p12File);
         }
@@ -37,7 +38,7 @@ export const buildCertSignFormData = (parameters: CertSignParameters, file: File
         break;
     }
   }
-  
+
   // Add signature appearance options if enabled
   if (parameters.showSignature) {
     formData.append('showSignature', 'true');
@@ -47,7 +48,7 @@ export const buildCertSignFormData = (parameters: CertSignParameters, file: File
     formData.append('pageNumber', parameters.pageNumber.toString());
     formData.append('showLogo', parameters.showLogo.toString());
   }
-  
+
   return formData;
 };
 
@@ -68,4 +69,4 @@ export const useCertSignOperation = () => {
     ...certSignOperationConfig,
     getErrorMessage: createStandardErrorHandler(t('certSign.error.failed', 'An error occurred while processing signatures.'))
   });
-};
+};