feat: implement form validation helpers and integrate field-level validation in agent profile screen, reset auth error suppression on login, and clean up home header UI.

lib/features/home/presentation/widgets/home_header.dart

@@ -401,17 +401,13 @@ class _MenuDrawer extends ConsumerWidget {
                                   ),
                                 ),
                                 const SizedBox(width: 8),
-                                const Padding(
-                                  padding: EdgeInsets.only(top: 1),
-                                  child: Text(
-                                    'Log In',
-                                    style: TextStyle(
-                                      fontFamily: 'Fractul',
-                                      fontSize: 16,
-                                      fontWeight: FontWeight.w700,
-                                      color: Colors.white,
-                                      height: 1.0,
-                                    ),
+                                const Text(
+                                  'Log In',
+                                  style: TextStyle(
+                                    fontFamily: 'Fractul',
+                                    fontSize: 16,
+                                    fontWeight: FontWeight.w700,
+                                    color: Colors.white,
                                   ),
                                 ),
                               ],