Auto-focus owner field and submit on Enter in register device dialog

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/lib/devices/device_actions.dart

@@ -58,7 +58,15 @@ Future<void> showRegisterDeviceDialog(
   final saved = await showDialog<bool>(
     context: context,
     builder: (context) => StatefulBuilder(
-      builder: (context, setDialogState) => AlertDialog(
+      builder: (context, setDialogState) {
+        void save() {
+          if (formKey.currentState?.validate() ?? false) {
+            formKey.currentState?.save();
+            Navigator.of(context).pop(true);
+          }
+        }
+
+        return AlertDialog(
           title: const Text('Register Device'),
           content: Form(
             key: formKey,
@@ -67,6 +75,8 @@ Future<void> showRegisterDeviceDialog(
               children: [
                 TextFormField(
                   decoration: const InputDecoration(labelText: 'Owner'),
+                  autofocus: true,
+                  onFieldSubmitted: (_) => save(),
                   validator: (value) => value == null || value.trim().isEmpty
                       ? 'Owner is required'
                       : null,
@@ -102,16 +112,12 @@ Future<void> showRegisterDeviceDialog(
               child: const Text('Cancel'),
             ),
             TextButton(
-            onPressed: () {
+              onPressed: save,
-              if (formKey.currentState?.validate() ?? false) {
-                formKey.currentState?.save();
-                Navigator.of(context).pop(true);
-              }
-            },
               child: const Text('Save'),
             ),
           ],
-      ),
+        );
+      },
     ),
   );