Refactor application submission response in ApplicationController to return JSON format and update phone number validation rule. Modify careers index view to handle new response structure.

app/Http/Controllers/ApplicationController.php

@@ -15,7 +15,7 @@ class ApplicationController extends Controller
             'birthdate' => 'required|date',
             'resume_file' => 'required|file|mimes:pdf,doc,docx|max:2048',
             'email' => 'required|email|max:255',
-            'phone_number' => 'required|string|max:20',
+            'phone_number' => 'required|string',
             'cover_letter' => 'nullable|string',
         ]);
 
@@ -31,6 +31,8 @@ class ApplicationController extends Controller
             'cover_letter' => $validatedData['cover_letter'] ?? null,
         ]);
 
-        return back()->with('success', 'Your application has been submitted successfully!');
+        return response()->json([
+            'message' => 'Your application has been submitted successfully!',
+        ]);
     }
 }