clear app db of channel messages on delete

we were only deleting channels and messages on device and the in app db would persist
this caused weird messages to later show up in other channels as they were deleted and
added due to the fact we store messages by channel index(slot #)

lib/screens/channels_screen.dart

@@ -3,6 +3,7 @@ import 'dart:math';
 import 'dart:typed_data';
 
 import 'package:flutter/material.dart';
+import 'package:meshcore_open/storage/channel_message_store.dart';
 import 'package:provider/provider.dart';
 import 'package:uuid/uuid.dart';
 
@@ -104,6 +105,7 @@ class _ChannelsScreenState extends State<ChannelsScreen>
   @override
   Widget build(BuildContext context) {
     final connector = context.watch<MeshCoreConnector>();
+    final channelMessageStore = ChannelMessageStore();
 
     // Auto-navigate back to scanner if disconnected
     if (!checkConnectionAndNavigate(connector)) {
@@ -304,6 +306,7 @@ class _ChannelsScreenState extends State<ChannelsScreen>
                             return _buildChannelTile(
                               context,
                               connector,
+                              channelMessageStore,
                               channel,
                               showDragHandle: true,
                               dragIndex: index,
@@ -323,6 +326,7 @@ class _ChannelsScreenState extends State<ChannelsScreen>
                             return _buildChannelTile(
                               context,
                               connector,
+                              channelMessageStore,
                               channel,
                             );
                           },
@@ -352,6 +356,7 @@ class _ChannelsScreenState extends State<ChannelsScreen>
   Widget _buildChannelTile(
     BuildContext context,
     MeshCoreConnector connector,
+    ChannelMessageStore channelMessageStore,
     Channel channel, {
     bool showDragHandle = false,
     int? dragIndex,
@@ -468,7 +473,12 @@ class _ChannelsScreenState extends State<ChannelsScreen>
             );
           }
         },
-        onLongPress: () => _showChannelActions(context, connector, channel),
+        onLongPress: () => _showChannelActions(
+          context,
+          connector,
+          channelMessageStore,
+          channel,
+        ),
       ),
     );
   }
@@ -476,6 +486,7 @@ class _ChannelsScreenState extends State<ChannelsScreen>
   void _showChannelActions(
     BuildContext context,
     MeshCoreConnector connector,
+    ChannelMessageStore channelMessageStore,
     Channel channel,
   ) {
     showModalBottomSheet(
@@ -505,7 +516,12 @@ class _ChannelsScreenState extends State<ChannelsScreen>
                 Navigator.pop(context);
                 await Future.delayed(const Duration(milliseconds: 100));
                 if (context.mounted) {
-                  _confirmDeleteChannel(context, connector, channel);
+                  _confirmDeleteChannel(
+                    context,
+                    connector,
+                    channelMessageStore,
+                    channel,
+                  );
                 }
               },
             ),
@@ -1451,6 +1467,7 @@ class _ChannelsScreenState extends State<ChannelsScreen>
   void _confirmDeleteChannel(
     BuildContext context,
     MeshCoreConnector connector,
+    ChannelMessageStore channelMessageStore,
     Channel channel,
   ) {
     showDialog(
@@ -1469,6 +1486,7 @@ class _ChannelsScreenState extends State<ChannelsScreen>
             onPressed: () {
               Navigator.pop(dialogContext);
               connector.deleteChannel(channel.index);
+              channelMessageStore.clearChannelMessages(channel.index);
               ScaffoldMessenger.of(context).showSnackBar(
                 SnackBar(
                   content: Text(