refactor: move modules under app/ directory and update file paths (#3938)

# Description of Changes

- **What was changed:**  
- Renamed top-level directories: `stirling-pdf` → `app/core`, `common` →
`app/common`, `proprietary` → `app/proprietary`.
- Updated all path references in `.gitattributes`, GitHub workflows
(`.github/workflows/*`), scripts (`.github/scripts/*`), `.gitignore`,
Dockerfiles, license files, and template settings to reflect the new
structure.
- Added a new CI job `check-generateOpenApiDocs` to generate and upload
OpenAPI documentation.
- Removed redundant `@Autowired` annotations from `TempFileShutdownHook`
and `UnlockPDFFormsController`.
- Minor formatting and comment adjustments in YAML templates and
resource files.

- **Why the change was made:**  
- To introduce a clear `app/` directory hierarchy for core, common, and
proprietary modules, improving organization and maintainability.
- To ensure continuous integration and Docker builds continue to work
seamlessly with the reorganized structure.
- To automate OpenAPI documentation generation as part of the CI
pipeline.

---

## 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/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)
- [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/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.

.github/workflows/build.yml

@@ -48,12 +48,12 @@ jobs:
         if: always()
         run: |
           declare -a dirs=(
-            "stirling-pdf/build/reports/tests/"
-            "stirling-pdf/build/test-results/"
-            "common/build/reports/tests/"
-            "common/build/test-results/"
-            "proprietary/build/reports/tests/"
-            "proprietary/build/test-results/"
+            "app/core/build/reports/tests/"
+            "app/core/build/test-results/"
+            "app/common/build/reports/tests/"
+            "app/common/build/test-results/"
+            "app/proprietary/build/reports/tests/"
+            "app/proprietary/build/test-results/"
           )
           missing_reports=()
           for dir in "${dirs[@]}"; do
@@ -74,19 +74,46 @@ jobs:
         with:
           name: test-reports-jdk-${{ matrix.jdk-version }}-spring-security-${{ matrix.spring-security }}
           path: |
-            stirling-pdf/build/reports/tests/
-            stirling-pdf/build/test-results/
-            stirling-pdf/build/reports/problems/
-            common/build/reports/tests/
-            common/build/test-results/
-            common/build/reports/problems/
-            proprietary/build/reports/tests/
-            proprietary/build/test-results/
-            proprietary/build/reports/problems/
+            app/core/build/reports/tests/
+            app/core/build/test-results/
+            app/core/build/reports/problems/
+            app/common/build/reports/tests/
+            app/common/build/test-results/
+            app/common/build/reports/problems/
+            app/proprietary/build/reports/tests/
+            app/proprietary/build/test-results/
+            app/proprietary/build/reports/problems/
             build/reports/problems/
           retention-days: 3
           if-no-files-found: warn
 
+  check-generateOpenApiDocs:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@6c439dc8bdf85cadbbce9ed30d1c7b959517bc49 # v2.12.2
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@c5195efecf7bdfc987ee8bae7a71cb8b11521c00 # v4.7.1
+        with:
+          java-version: "17"
+          distribution: "temurin"
+
+      - uses: gradle/actions/setup-gradle@ac638b010cf58a27ee6c972d7336334ccaf61c96 # v4.4.1
+
+      - name: Generate OpenAPI documentation
+        run: ./gradlew :stirling-pdf:generateOpenApiDocs
+      
+      - name: Upload OpenAPI Documentation
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: openapi-docs
+          path: ./SwaggerDoc.json
+
   check-licence:
     runs-on: ubuntu-latest
     steps: