feat: add error handling examples and tests for SDK clarity (#103)

Co-authored-by: Claude <noreply@anthropic.com>

Author: tysonwil

mobile/with-expo/ios/paraexpo/Images.xcassets/AppIcon.appiconset/App-Icon-1024x1024@1x.png

@@ -1,14 +1,14 @@
 {
-  "images": [
+  "images" : [
     {
-      "filename": "App-Icon-1024x1024@1x.png",
-      "idiom": "universal",
-      "platform": "ios",
-      "size": "1024x1024"
+      "filename" : "image.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
     }
   ],
-  "info": {
-    "version": 1,
-    "author": "expo"
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
   }
-}
+}

mobile/with-expo/ios/paraexpo/Images.xcassets/AppIcon.appiconset/Contents.json

@@ -763,6 +763,7 @@ class _CosmosWalletViewState extends State<CosmosWalletView> {
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
     return Scaffold(
+      key: const Key('walletDetailView'),
       backgroundColor: theme.scaffoldBackgroundColor,
       appBar: AppBar(
         backgroundColor: theme.scaffoldBackgroundColor,

mobile/with-expo/ios/paraexpo/Images.xcassets/AppIcon.appiconset/image.png

@@ -345,6 +345,7 @@ class _EVMWalletViewState extends State<EVMWalletView> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
+      key: const Key('walletDetailView'),
       backgroundColor: Theme.of(context).colorScheme.surface,
       appBar: AppBar(
         backgroundColor: Theme.of(context).colorScheme.surface,
@@ -506,6 +507,7 @@ class _EVMWalletViewState extends State<EVMWalletView> {
                       SizedBox(
                         width: double.infinity,
                         child: ElevatedButton(
+                          key: const Key('signMessageButton'),
                           onPressed: _isLoading || _messageToSign.isEmpty
                               ? null
                               : _signMessage,

mobile/with-flutter/lib/features/wallets/screens/details/cosmos_wallet_view.dart

@@ -356,6 +356,7 @@ class _SolanaWalletViewState extends State<SolanaWalletView> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
+      key: const Key('walletDetailView'),
       backgroundColor: Theme.of(context).colorScheme.surface,
       appBar: AppBar(
         backgroundColor: Theme.of(context).colorScheme.surface,
@@ -575,6 +576,7 @@ class _SolanaWalletViewState extends State<SolanaWalletView> {
                           const SizedBox(width: 12),
                           Expanded(
                             child: ElevatedButton(
+                              key: const Key('signTransactionButton'),
                               onPressed: _isLoading ? null : _signTransaction,
                               style: ElevatedButton.styleFrom(
                                 backgroundColor: Colors.grey[300],

mobile/with-flutter/lib/features/wallets/screens/details/evm_wallet_view.dart

@@ -17,6 +17,7 @@ class WalletCard extends StatelessWidget {
     final chain = wallet.type?.toChain ?? WalletChain.evm;
 
     return GestureDetector(
+      key: Key('walletCell_${wallet.type?.value ?? 'unknown'}'),
       onTap: onTap,
       child: Container(
         height: 150,

mobile/with-flutter/lib/features/wallets/screens/details/solana_wallet_view.dart

@@ -358,6 +358,7 @@ class _AuthScreenState extends State<AuthScreen> {
               const SizedBox(height: 24),
               // Email/Phone input
               EmailPhoneInput(
+                key: const Key('emailPhoneInput'),
                 onSubmit: _isProcessing ? (_, __) {} : _handleEmailPhone,
               ),
               const SizedBox(height: 20),

mobile/with-flutter/lib/features/wallets/widgets/wallet_card.dart

@@ -49,13 +49,18 @@ void main(List<String> args) async {
       case 'wallets':
         testFiles = ['evm_wallet_test.dart', 'solana_wallet_test.dart', 'cosmos_wallet_test.dart'];
         break;
+      case 'error':
+      case 'errors':
+        testFiles = ['simple_error_test.dart'];
+        break;
       case 'all':
       default:
         testFiles = [
           'authentication_test.dart',
           'evm_wallet_test.dart',
           'solana_wallet_test.dart',
-          'cosmos_wallet_test.dart'
+          'cosmos_wallet_test.dart',
+          'simple_error_test.dart'
         ];
         break;
     }

mobile/with-flutter/lib/screens/auth_screen.dart

@@ -218,7 +218,7 @@ struct AuthView: View {
                 }
             } catch {
                 // Handle any errors
-                errorMessage = error.localizedDescription
+                errorMessage = (error as? LocalizedError)?.errorDescription ?? error.localizedDescription
                 showErrorAlert = true
             }
         }