Add REST annotations and refactor properties file handling

Introduced `@RestController` and `@RequestMapping` in `StaffAppController` for standardized API endpoints. Refactored properties file handling in `PropertiesLoader` and `PropertiesWriter` to simplify file creation logic.

src/main/java/com/alttd/forms/properties/PropertiesLoader.java

@@ -26,7 +26,7 @@ public class PropertiesLoader {
             }
             file = new File(currentJarPath.get(), fileName);
         } else {
-            file = Path.of(URI.create("file://" + path + File.separator + fileName)).toFile();
+            file = new File(path, fileName);
         }
 
 

src/main/java/com/alttd/forms/properties/PropertiesWriter.java

@@ -25,7 +25,7 @@ public class PropertiesWriter {
             }
             file = new File(currentJarPath.get(), fileName);
         } else {
-            file = Path.of(URI.create("file://" + path + File.separator + fileName)).toFile();
+            file = new File(path, fileName);
         }
 
         if (file.exists()) {