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.

testing/test.sh

@@ -182,17 +182,17 @@ get_expected_version() {
 verify_app_version() {
     local service_name=$1
     local base_url=$2
-    
+
     echo "Checking version for $service_name (expecting $EXPECTED_VERSION)..."
-    
+
     # Try to access the homepage and extract the version
     local response
     response=$(curl -s "$base_url")
-    
+
     # Extract version from pixel tracking tag
     local actual_version
     actual_version=$(echo "$response" | grep -o 'appVersion=[0-9.]*' | head -1 | sed 's/appVersion=//')
-    
+
     # If we couldn't find the version in the pixel tag, try other approaches
     if [ -z "$actual_version" ]; then
         # Check for "App Version:" format
@@ -203,7 +203,7 @@ verify_app_version() {
             return 1
         fi
     fi
-    
+
     # Check if the extracted version matches expected version
     if [ "$actual_version" = "$EXPECTED_VERSION" ]; then
         echo "✅ Version verification passed: $actual_version"
@@ -264,13 +264,13 @@ main() {
     export DOCKER_CLI_EXPERIMENTAL=enabled
     export COMPOSE_DOCKER_CLI_BUILD=0
     export DISABLE_ADDITIONAL_FEATURES=true
-    
+
     # Run the gradlew build command and check if it fails
     if ! ./gradlew clean build; then
         echo "Gradle build failed with security disabled, exiting script."
         exit 1
     fi
-    
+
     # Get expected version after the build to ensure version.properties is created
     echo "Getting expected version from Gradle..."
     EXPECTED_VERSION=$(get_expected_version)
@@ -292,7 +292,7 @@ main() {
         echo "Webpage accessibility lite tests failed"
     fi
     cd "$PROJECT_ROOT"
-    
+
     echo "Testing version verification..."
     if verify_app_version "Stirling-PDF-Ultra-Lite" "http://localhost:8080"; then
         passed_tests+=("Stirling-PDF-Ultra-Lite-Version-Check")
@@ -301,7 +301,7 @@ main() {
         failed_tests+=("Stirling-PDF-Ultra-Lite-Version-Check")
         echo "Version verification failed for Stirling-PDF-Ultra-Lite"
     fi
-    
+
     docker-compose -f "./exampleYmlFiles/docker-compose-latest-ultra-lite.yml" down
 
     # run_tests "Stirling-PDF" "./exampleYmlFiles/docker-compose-latest.yml"
@@ -313,7 +313,7 @@ main() {
         echo "Gradle build failed with security enabled, exiting script."
         exit 1
     fi
-    
+
     # Get expected version after the security-enabled build
     echo "Getting expected version from Gradle (security enabled)..."
     EXPECTED_VERSION=$(get_expected_version)
@@ -343,7 +343,7 @@ main() {
         echo "Webpage accessibility full tests failed"
     fi
     cd "$PROJECT_ROOT"
-    
+
     echo "Testing version verification..."
     if verify_app_version "Stirling-PDF-Security-Fat" "http://localhost:8080"; then
         passed_tests+=("Stirling-PDF-Security-Fat-Version-Check")
@@ -420,7 +420,7 @@ main() {
         failed_tests+=("Disabled-Endpoints")
         echo "Disabled Endpoints tests failed"
     fi
-    
+
     echo "Testing version verification..."
     if verify_app_version "Stirling-PDF-Fat-Disable-Endpoints" "http://localhost:8080"; then
         passed_tests+=("Stirling-PDF-Fat-Disable-Endpoints-Version-Check")