feat: implement email change request functionality with verification dialog

lib/features/profile/data/profile_repository.dart

@@ -207,6 +207,28 @@ class ProfileRepository {
     }
   }
 
+  /// Request email change: POST /auth/change-email
+  /// Backend sends a verification link to [newEmail]; email is only
+  /// persisted once the link is clicked.
+  Future<String> requestEmailChange(String newEmail, String password) async {
+    try {
+      final response = await _dio.post('/auth/change-email', data: {
+        'newEmail': newEmail,
+        'password': password,
+      });
+      return (response.data?['data']?['message'] as String?) ??
+          'Verification link sent';
+    } on DioException catch (e) {
+      if (e.error is ApiException) throw e.error as ApiException;
+      throw ApiException(
+        message: e.response?.data?['message'] ??
+            e.message ??
+            'Failed to request email change',
+        statusCode: e.response?.statusCode,
+      );
+    }
+  }
+
   /// Fetch notification preferences.
   /// Agent: GET /agents/preferences/notifications
   /// User: GET /users/preferences/notifications

lib/features/profile/presentation/widgets/profile_settings_tab.dart

@@ -256,11 +256,37 @@ class _ProfileSettingsTabState extends ConsumerState<ProfileSettingsTab> {
           ),
         ],
         const SizedBox(height: 24),
-        ProfileFormField(
+        Row(
-            label: 'Email Address',
+          crossAxisAlignment: CrossAxisAlignment.end,
-            controller: _emailController,
+          children: [
-            enabled: false,
+            Expanded(
-            textCapitalization: TextCapitalization.none),
+              child: ProfileFormField(
+                  label: 'Email Address',
+                  controller: _emailController,
+                  enabled: false,
+                  textCapitalization: TextCapitalization.none),
+            ),
+            const SizedBox(width: 8),
+            Padding(
+              padding: const EdgeInsets.only(bottom: 4),
+              child: TextButton(
+                onPressed: _openChangeEmailDialog,
+                style: TextButton.styleFrom(
+                  foregroundColor: AppColors.accentOrange,
+                  padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
+                ),
+                child: const Text(
+                  'Change',
+                  style: TextStyle(
+                    fontFamily: 'SourceSerif4',
+                    fontWeight: FontWeight.w600,
+                    fontSize: 13,
+                  ),
+                ),
+              ),
+            ),
+          ],
+        ),
         const SizedBox(height: 24),
         ProfileFormField(
           label: 'Phone Number',
@@ -403,4 +429,109 @@ class _ProfileSettingsTabState extends ConsumerState<ProfileSettingsTab> {
       ),
     );
   }
+
+  Future<void> _openChangeEmailDialog() async {
+    final newEmailCtl = TextEditingController();
+    final passwordCtl = TextEditingController();
+    String? localError;
+    bool submitting = false;
+
+    await showDialog<void>(
+      context: context,
+      builder: (dialogCtx) {
+        return StatefulBuilder(
+          builder: (dialogCtx, setDialogState) {
+            Future<void> submit() async {
+              final email = newEmailCtl.text.trim();
+              final pw = passwordCtl.text;
+              if (email.isEmpty || pw.isEmpty) {
+                setDialogState(() => localError =
+                    'Please enter a new email and your current password');
+                return;
+              }
+              setDialogState(() {
+                submitting = true;
+                localError = null;
+              });
+              try {
+                final repo = ref.read(profileRepositoryProvider);
+                final message = await repo.requestEmailChange(email, pw);
+                if (dialogCtx.mounted) Navigator.of(dialogCtx).pop();
+                if (mounted) _showSnackBar(message);
+              } catch (e) {
+                setDialogState(() {
+                  submitting = false;
+                  localError = e.toString().replaceFirst('Exception: ', '');
+                });
+              }
+            }
+
+            return AlertDialog(
+              title: const Text('Change Email Address'),
+              content: SingleChildScrollView(
+                child: Column(
+                  mainAxisSize: MainAxisSize.min,
+                  crossAxisAlignment: CrossAxisAlignment.stretch,
+                  children: [
+                    const Text(
+                      'A verification link will be sent to your new email. Your email changes only after you click the link.',
+                      style: TextStyle(fontSize: 13),
+                    ),
+                    const SizedBox(height: 16),
+                    TextField(
+                      controller: newEmailCtl,
+                      keyboardType: TextInputType.emailAddress,
+                      autocorrect: false,
+                      textCapitalization: TextCapitalization.none,
+                      decoration: const InputDecoration(
+                        labelText: 'New Email',
+                        hintText: 'new@example.com',
+                      ),
+                    ),
+                    const SizedBox(height: 12),
+                    TextField(
+                      controller: passwordCtl,
+                      obscureText: true,
+                      decoration: const InputDecoration(
+                        labelText: 'Current Password',
+                      ),
+                    ),
+                    if (localError != null) ...[
+                      const SizedBox(height: 12),
+                      Text(
+                        localError!,
+                        style: const TextStyle(
+                          color: Colors.red,
+                          fontSize: 12,
+                        ),
+                      ),
+                    ],
+                  ],
+                ),
+              ),
+              actions: [
+                TextButton(
+                  onPressed: submitting
+                      ? null
+                      : () => Navigator.of(dialogCtx).pop(),
+                  child: const Text('Cancel'),
+                ),
+                ElevatedButton(
+                  onPressed: submitting ? null : submit,
+                  style: ElevatedButton.styleFrom(
+                    backgroundColor: AppColors.accentOrange,
+                    foregroundColor: Colors.white,
+                  ),
+                  child: Text(submitting ? 'Sending...' : 'Send Link'),
+                ),
+              ],
+            );
+          },
+        );
+      },
+    );
+
+    newEmailCtl.dispose();
+    passwordCtl.dispose();
+  }
 }