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.

scripts/PropSync.java

@@ -9,7 +9,7 @@ import java.util.*;
 public class PropSync {
 
     public static void main(String[] args) throws IOException {
-        File folder = new File("C:\\Users\\systo\\git\\Stirling-PDF\\src\\main\\resources");
+        File folder = new File("C:\\Users\\systo\\git\\Stirling-PDF\\app\\core\\src\\main\\resources");
         File[] files = folder.listFiles((dir, name) -> name.matches("messages_.*\\.properties"));
 
         List<String> enLines = Files.readAllLines(Paths.get(folder + "\\messages_en_GB.properties"), StandardCharsets.UTF_8);

scripts/counter_translation.py

@@ -207,7 +207,7 @@ def compare_files(
 
 
 if __name__ == "__main__":
-    directory = os.path.join(os.getcwd(), "stirling-pdf", "src", "main", "resources")
+    directory = os.path.join(os.getcwd(), "app", "core", "src", "main", "resources")
     messages_file_paths = glob.glob(os.path.join(directory, "messages_*.properties"))
     reference_file = os.path.join(directory, "messages_en_GB.properties")
 

scripts/init-without-ocr.sh

@@ -20,7 +20,7 @@ if [[ "$INSTALL_BOOK_AND_ADVANCED_HTML_OPS" == "true" && "$FAT_DOCKER" != "true"
 fi
 
 if [[ "$FAT_DOCKER" != "true" ]]; then
-  /scripts/download-security-jar.sh	
+  /scripts/download-security-jar.sh
 fi
 
 if [[ -n "$LANGS" ]]; then

scripts/init.sh

@@ -33,4 +33,4 @@ mkdir -p /tmp/stirling-pdf || true
 chown -R stirlingpdfuser:stirlingpdfgroup /tmp/stirling-pdf || true
 chmod -R 755 /tmp/stirling-pdf || true
 
-/scripts/init-without-ocr.sh "$@"
+/scripts/init-without-ocr.sh "$@"

scripts/remove_translation_keys.sh

@@ -8,7 +8,7 @@ fi
 
 key_to_remove="$1"
 
-for file in ../src/main/resources/messages_*.properties; do
+for file in ../app/core/src/main/resources/messages_*.properties; do
     # If the key ends with a dot, remove all keys starting with it
     if [[ "$key_to_remove" == *. ]]; then
         sed -i "/^${key_to_remove//./\\.}/d" "$file"
@@ -17,4 +17,4 @@ for file in ../src/main/resources/messages_*.properties; do
         sed -i "/^${key_to_remove//./\\.}=/d" "$file"
     fi
     echo "Updated $file"
-done
+done

scripts/replace_translation_line.sh

@@ -4,7 +4,7 @@ translation_key="pdfToPDFA.credit"
 old_value="qpdf"
 new_value="liibreoffice"
 
-for file in ../src/main/resources/messages_*.properties; do
+for file in ../app/core/src/main/resources/messages_*.properties; do
   sed -i "/^$translation_key=/s/$old_value/$new_value/" "$file"
   echo "Updated $file"
 done