🔄 Changes

Core Features
Unread Message Tracking: Added persistent unread counts for contacts and channels with visual badges
Message Deletion: Users can now long-press to delete individual messages in chats and channels
SMAZ Compression: Added per-contact compression settings (previously only channels)
UTF-8 Length Limiting: Text inputs now enforce protocol byte limits correctly
Channel Message Paths: New screen to visualize packet routing through repeater network with map view
Protocol Updates
Added maxContactMessageBytes() and maxChannelMessageBytes() helpers for message length validation
Changed channel PSK format from Base64 to Hexadecimal (breaking change)
Added app version field to connection handshake frame
UI Improvements
Unread badges on all contact and channel list items
Enhanced message bubbles with path visualization for channel messages
Character count displays in message input fields
Improved repeater CLI screen functionality
New Files
lib/storage/unread_store.dart - Unread tracking persistence
lib/storage/contact_settings_store.dart - Per-contact SMAZ settings
lib/widgets/unread_badge.dart - Unread count indicator
lib/helpers/utf8_length_limiter.dart - Byte-aware text input formatter
lib/screens/channel_message_path_screen.dart - Packet path visualization

lib/screens/channel_chat_screen.dart

@@ -1,15 +1,20 @@
+import 'dart:convert';
 import 'dart:typed_data';
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:latlong2/latlong.dart';
 import 'package:provider/provider.dart';
 
 import '../connector/meshcore_connector.dart';
+import '../connector/meshcore_protocol.dart';
+import '../helpers/utf8_length_limiter.dart';
 import '../models/channel.dart';
 import '../models/channel_message.dart';
 import '../utils/emoji_utils.dart';
 import '../widgets/gif_message.dart';
 import '../widgets/gif_picker.dart';
+import 'channel_message_path_screen.dart';
 import 'map_screen.dart';
 
 class ChannelChatScreen extends StatefulWidget {
@@ -28,8 +33,18 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
   final TextEditingController _textController = TextEditingController();
   final ScrollController _scrollController = ScrollController();
 
+  @override
+  void initState() {
+    super.initState();
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
+      context.read<MeshCoreConnector>().setActiveChannel(widget.channel.index);
+    });
+  }
+
   @override
   void dispose() {
+    context.read<MeshCoreConnector>().setActiveChannel(null);
     _textController.dispose();
     _scrollController.dispose();
     super.dispose();
@@ -66,9 +81,17 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
                         : widget.channel.name,
                     style: const TextStyle(fontSize: 16),
                   ),
-                  Text(
-                    widget.channel.isPublicChannel ? 'Public' : 'Private',
-                    style: const TextStyle(fontSize: 12),
+                  Consumer<MeshCoreConnector>(
+                    builder: (context, connector, _) {
+                      final unreadCount =
+                          connector.getUnreadCountForChannelIndex(widget.channel.index);
+                      final privacy = widget.channel.isPublicChannel ? 'Public' : 'Private';
+                      return Text(
+                        '$privacy • Unread: $unreadCount',
+                        overflow: TextOverflow.ellipsis,
+                        style: const TextStyle(fontSize: 12),
+                      );
+                    },
                   ),
                 ],
               ),
@@ -158,7 +181,8 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
           ],
           Flexible(
             child: GestureDetector(
-              onLongPress: () => _showMessagePathInfo(message),
+              onTap: () => _showMessagePathInfo(message),
+              onLongPress: () => _showMessageActions(message),
               child: Container(
                 padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
                 constraints: BoxConstraints(
@@ -383,6 +407,8 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
   }
 
   Widget _buildMessageComposer() {
+    final connector = context.watch<MeshCoreConnector>();
+    final maxBytes = maxChannelMessageBytes(connector.selfName);
     return Container(
       padding: const EdgeInsets.all(8),
       decoration: BoxDecoration(
@@ -432,6 +458,9 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
 
                 return TextField(
                   controller: _textController,
+                  inputFormatters: [
+                    Utf8LengthLimitingTextInputFormatter(maxBytes),
+                  ],
                   decoration: InputDecoration(
                     hintText: 'Type a message...',
                     border: OutlineInputBorder(
@@ -464,7 +493,16 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
     final text = _textController.text.trim();
     if (text.isEmpty) return;
 
-    context.read<MeshCoreConnector>().sendChannelMessage(widget.channel, text);
+    final connector = context.read<MeshCoreConnector>();
+    final maxBytes = maxChannelMessageBytes(connector.selfName);
+    if (utf8.encode(text).length > maxBytes) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text('Message too long (max $maxBytes bytes).')),
+      );
+      return;
+    }
+
+    connector.sendChannelMessage(widget.channel, text);
     _textController.clear();
   }
 
@@ -480,65 +518,67 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
   }
 
   void _showMessagePathInfo(ChannelMessage message) {
-    final pathPrefixes =
-        message.pathBytes.isNotEmpty ? _formatPathPrefixes(message.pathBytes) : null;
-    showDialog(
-      context: context,
-      builder: (context) => AlertDialog(
-        title: const Text('Packet Path'),
-        content: Column(
-          mainAxisSize: MainAxisSize.min,
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: [
-            _buildDetailRow('Sender', message.senderName),
-            _buildDetailRow('Time', _formatTime(message.timestamp)),
-            _buildDetailRow('Repeats', message.repeatCount.toString()),
-            _buildDetailRow('Path', _formatPathLabel(message.pathLength)),
-            if (pathPrefixes != null) _buildDetailRow('Prefixes', pathPrefixes),
-            if (pathPrefixes == null) ...[
-              const SizedBox(height: 8),
-              const Text(
-                'Hop details are not provided for this packet.',
-                style: TextStyle(fontSize: 11, color: Colors.grey),
-              ),
-            ],
-          ],
-        ),
-        actions: [
-          TextButton(
-            onPressed: () => Navigator.pop(context),
-            child: const Text('Close'),
-          ),
-        ],
+    Navigator.push(
+      context,
+      MaterialPageRoute(
+        builder: (context) => ChannelMessagePathScreen(message: message),
       ),
     );
   }
 
-  String _formatPathLabel(int? pathLength) {
-    if (pathLength == null) return 'Unknown';
-    if (pathLength < 0) return 'Flood';
-    if (pathLength == 0) return 'Direct';
-    return '$pathLength hops';
+  void _showMessageActions(ChannelMessage message) {
+    showModalBottomSheet(
+      context: context,
+      builder: (sheetContext) => SafeArea(
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            ListTile(
+              leading: const Icon(Icons.copy),
+              title: const Text('Copy'),
+              onTap: () {
+                Navigator.pop(sheetContext);
+                _copyMessageText(message.text);
+              },
+            ),
+            ListTile(
+              leading: const Icon(Icons.delete_outline),
+              title: const Text('Delete'),
+              onTap: () async {
+                Navigator.pop(sheetContext);
+                await _deleteMessage(message);
+              },
+            ),
+            ListTile(
+              leading: const Icon(Icons.close),
+              title: const Text('Cancel'),
+              onTap: () => Navigator.pop(sheetContext),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+
+  void _copyMessageText(String text) {
+    Clipboard.setData(ClipboardData(text: text));
+    ScaffoldMessenger.of(context).showSnackBar(
+      const SnackBar(content: Text('Message copied')),
+    );
+  }
+
+  Future<void> _deleteMessage(ChannelMessage message) async {
+    await context.read<MeshCoreConnector>().deleteChannelMessage(message);
+    if (!mounted) return;
+    ScaffoldMessenger.of(context).showSnackBar(
+      const SnackBar(content: Text('Message deleted')),
+    );
   }
 
   String _formatPathPrefixes(Uint8List pathBytes) {
-    return pathBytes.map((b) => b.toRadixString(16).padLeft(2, '0')).join(',');
-  }
-
-  Widget _buildDetailRow(String label, String value) {
-    return Padding(
-      padding: const EdgeInsets.symmetric(vertical: 2),
-      child: Row(
-        crossAxisAlignment: CrossAxisAlignment.start,
-        children: [
-          SizedBox(
-            width: 70,
-            child: Text(label, style: TextStyle(color: Colors.grey[600])),
-          ),
-          Expanded(child: Text(value)),
-        ],
-      ),
-    );
+    return pathBytes
+        .map((b) => b.toRadixString(16).padLeft(2, '0').toUpperCase())
+        .join(',');
   }
 }