TimeZone support

lib/BlindMasterScreens/groupControl/create_group_dialog.dart

@@ -2,6 +2,7 @@ import 'dart:convert';
 
 import 'package:blind_master/BlindMasterResources/secure_transmissions.dart';
 import 'package:blind_master/BlindMasterResources/text_inputs.dart';
+import 'package:blind_master/BlindMasterResources/timezone_picker.dart';
 import 'package:flutter/material.dart';
 import 'package:google_fonts/google_fonts.dart';
 
@@ -17,6 +18,7 @@ class _CreateGroupDialogState extends State<CreateGroupDialog> {
   List<Map<String, dynamic>> devices = [];
   Map<int, List<Map<String, dynamic>>> devicePeripherals = {};
   Set<int> selectedPeripheralIds = {};
+  String? _selectedTimezone;
   bool isLoading = true;
   String? errorMessage;
 
@@ -108,6 +110,7 @@ class _CreateGroupDialogState extends State<CreateGroupDialog> {
         {
           'name': _nameController.text.trim(),
           'peripheral_ids': selectedPeripheralIds.toList(),
+          if (_selectedTimezone != null) 'timezone': _selectedTimezone,
         },
         'add_group'
       );
@@ -164,6 +167,12 @@ class _CreateGroupDialogState extends State<CreateGroupDialog> {
                     }
                   },
                 ),
+                const SizedBox(height: 12),
+                TimezonePicker(
+                  value: _selectedTimezone,
+                  label: 'Group Timezone (optional)',
+                  onChanged: (tz) => setState(() => _selectedTimezone = tz),
+                ),
                 const SizedBox(height: 16),
                 Container(
                   padding: const EdgeInsets.all(10),