feat:centralise temp-file management & cleanup across app/docker (#3797)

# Description of Changes
Introduces TempFileManager, registry, and scheduled cleanup service;
aligns all Docker images and runtime scripts to use a dedicated
/tmp/stirling-pdf directory; updates controllers, utilities, and tests
to use the new API; adds configurable system.tempFileManagement section.

Closes #(issue_number)

---

## 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/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/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/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/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: a <a>

scripts/init-without-ocr.sh

@@ -28,9 +28,11 @@ if [[ -n "$LANGS" ]]; then
 fi
 
 echo "Setting permissions and ownership for necessary directories..."
+# Ensure temp directory exists and has correct permissions
+mkdir -p /tmp/stirling-pdf || true
 # Attempt to change ownership of directories and files
-if chown -R stirlingpdfuser:stirlingpdfgroup $HOME /logs /scripts /usr/share/fonts/opentype/noto /configs /customFiles /pipeline /app.jar; then
-	chmod -R 755 /logs /scripts /usr/share/fonts/opentype/noto /configs /customFiles /pipeline /app.jar || true
+if chown -R stirlingpdfuser:stirlingpdfgroup $HOME /logs /scripts /usr/share/fonts/opentype/noto /configs /customFiles /pipeline /tmp/stirling-pdf /app.jar; then
+	chmod -R 755 /logs /scripts /usr/share/fonts/opentype/noto /configs /customFiles /pipeline /tmp/stirling-pdf /app.jar || true
     # If chown succeeds, execute the command as stirlingpdfuser
     exec su-exec stirlingpdfuser "$@"
 else