Builds custom Jar (#5029)

# Description of Changes

Change jar files to contain frontend if provided with param, else
doesnt... add release artifact -server version which wont have frontend

---

## 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.

.gitignore

@@ -17,8 +17,8 @@ local.properties
 version.properties
 
 #### Stirling-PDF Files ###
-pipeline/watchedFolders/
-pipeline/finishedFolders/
+pipeline/
+!pipeline/.gitkeep
 customFiles/
 configs/
 watchedFolders/
@@ -31,6 +31,20 @@ exampleYmlFiles/stirling/
 /testing/file_snapshots
 SwaggerDoc.json
 
+# Frontend build artifacts copied to backend static resources
+# These are generated by npm build and should not be committed
+app/core/src/main/resources/static/assets/
+app/core/src/main/resources/static/index.html
+app/core/src/main/resources/static/locales/
+app/core/src/main/resources/static/Login/
+app/core/src/main/resources/static/classic-logo/
+app/core/src/main/resources/static/modern-logo/
+app/core/src/main/resources/static/og_images/
+app/core/src/main/resources/static/samples/
+app/core/src/main/resources/static/manifest-classic.json
+app/core/src/main/resources/static/robots.txt
+# Note: Keep backend-managed files like fonts/, css/, js/, pdfjs/, etc.
+
 # Gradle
 .gradle
 .gradle-home