refactor: Update Twitter OAuth 2.0 PKCE flow for dynamic redirect URI and public client authentication, replace SVG back button with a native icon, and enhance Twitter login error reporting.

lib/features/agents/presentation/screens/agent_edit_profile_screen.dart

@@ -7,7 +7,6 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 import 'package:image_picker/image_picker.dart';
 import 'package:intl/intl.dart';
-import 'package:flutter_svg/flutter_svg.dart';
 import 'package:real_estate_mobile/core/constants/app_colors.dart';
 import 'package:real_estate_mobile/features/profile/data/profile_repository.dart';
 
@@ -343,17 +342,31 @@ class _AgentEditProfileScreenState
 
     return Column(
       children: [
-        // Header with circular back button (SVG) matching Figma
+        // Header with back button
         Padding(
-          padding: const EdgeInsets.fromLTRB(16, 4, 16, 8),
+          padding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
           child: Row(
             children: [
               GestureDetector(
-                onTap: () => context.pop(),
-                child: SvgPicture.asset(
-                  'assets/icons/back_circle_icon.svg',
-                  width: 32,
-                  height: 32,
+                onTap: () {
+                  if (Navigator.of(context).canPop()) {
+                    Navigator.of(context).pop();
+                  } else {
+                    context.go('/home');
+                  }
+                },
+                child: Container(
+                  width: 36,
+                  height: 36,
+                  decoration: BoxDecoration(
+                    color: AppColors.primaryDark.withValues(alpha: 0.08),
+                    shape: BoxShape.circle,
+                  ),
+                  child: const Icon(
+                    Icons.arrow_back_ios_new_rounded,
+                    color: AppColors.primaryDark,
+                    size: 18,
+                  ),
                 ),
               ),
               const SizedBox(width: 12),