chore: Improve VSCode Java Project Configuration with Explicit Source Paths (#3699)

# Description of Changes

- **What was changed**:  
Added `"java.project.sourcePaths"` configuration to
`.vscode/settings.json` to explicitly define the Java source
directories:
  - `stirling-pdf/src/main/java`  
  - `common/src/main/java`  
  - `proprietary/src/main/java`

- **Why the change was made**:  
Ensures VSCode correctly recognizes all relevant source folders for Java
compilation, navigation, and language features—especially important for
multi-module setups.

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] 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)
- [x] I have performed a self-review of my own code
- [x] 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.

.vscode/settings.json

@@ -86,4 +86,9 @@
   "spring.initializr.defaultLanguage": "Java",
   "spring.initializr.defaultGroupId": "stirling.software.SPDF",
   "spring.initializr.defaultArtifactId": "SPDF",
+  "java.project.sourcePaths": [
+    "stirling-pdf/src/main/java",
+    "common/src/main/java",
+    "proprietary/src/main/java"
+  ],
 }