Add REST annotations to StaffAppController

Introduce `@RestController` and `@RequestMapping` annotations to the `StaffAppController` class. This change standardizes the API endpoint and ensures all methods within this class are mapped correctly under `/api/apply`.

src/main/java/com/alttd/forms/apply/StaffAppController.java

@@ -10,12 +10,15 @@ import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
 
 import java.util.concurrent.CompletableFuture;
 
+@RestController
+@RequestMapping("/api/apply")
 public class StaffAppController {
 
-
     private static final Logger logger = LoggerFactory.getLogger(StaffAppController.class);
 
     @PostMapping("/staffApplication")