Add DuplicateSpaceDialog widget for user interaction in duplicate space management.

lib/pages/space_management_v2/modules/duplicate_space/presentation/views/duplicate_space_dialog.dart

@@ -0,0 +1,68 @@
+import 'package:flutter/material.dart';
+import 'package:syncrow_web/pages/space_management_v2/modules/duplicate_space/presentation/widgets/duplicate_space_text_field.dart';
+
+class DuplicateSpaceDialog extends StatefulWidget {
+  const DuplicateSpaceDialog({
+    required this.initialName,
+    required this.onSubmit,
+    super.key,
+  });
+
+  final String initialName;
+  final void Function(String) onSubmit;
+
+  @override
+  State<DuplicateSpaceDialog> createState() => _DuplicateSpaceDialogState();
+}
+
+class _DuplicateSpaceDialogState extends State<DuplicateSpaceDialog> {
+  late final TextEditingController _nameController;
+  bool _isNameValid = true;
+
+  @override
+  void initState() {
+    super.initState();
+    _nameController = TextEditingController(text: '${widget.initialName}(1)');
+    _nameController.addListener(_validateName);
+  }
+
+  void _validateName() => setState(
+        () => _isNameValid = _nameController.text.trim() != widget.initialName,
+      );
+
+  @override
+  void dispose() {
+    _nameController.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: const SelectableText('Duplicate Space'),
+      content: Column(
+        mainAxisSize: MainAxisSize.min,
+        spacing: 16,
+        children: [
+          const SelectableText('Enter a new name for the duplicated space:'),
+          DuplicateSpaceTextField(
+            nameController: _nameController,
+            isNameValid: _isNameValid,
+            initialName: widget.initialName,
+          ),
+        ],
+      ),
+      actions: [
+        TextButton(
+          onPressed: Navigator.of(context).pop,
+          child: const Text('Cancel'),
+        ),
+        TextButton(
+          onPressed:
+              _isNameValid ? () => widget.onSubmit(_nameController.text) : null,
+          child: const Text('Duplicate'),
+        ),
+      ],
+    );
+  }
+}