🔄 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/chat_screen.dart

@@ -1,13 +1,19 @@
+import 'dart:convert';
 import 'dart:typed_data';
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:provider/provider.dart';
 import 'package:latlong2/latlong.dart';
 
 import '../connector/meshcore_connector.dart';
+import '../connector/meshcore_protocol.dart';
+import '../helpers/utf8_length_limiter.dart';
+import '../models/channel_message.dart';
 import '../models/contact.dart';
 import '../models/message.dart';
 import '../services/path_history_service.dart';
+import 'channel_message_path_screen.dart';
 import 'map_screen.dart';
 import '../utils/emoji_utils.dart';
 import '../widgets/gif_message.dart';
@@ -27,8 +33,18 @@ class _ChatScreenState extends State<ChatScreen> {
   final _scrollController = ScrollController();
   bool _forceFlood = false;
 
+  @override
+  void initState() {
+    super.initState();
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
+      context.read<MeshCoreConnector>().setActiveContact(widget.contact.publicKeyHex);
+    });
+  }
+
   @override
   void dispose() {
+    context.read<MeshCoreConnector>().setActiveContact(null);
     _textController.dispose();
     _scrollController.dispose();
     super.dispose();
@@ -43,6 +59,8 @@ class _ChatScreenState extends State<ChatScreen> {
             final paths = pathService.getRecentPaths(widget.contact.publicKeyHex);
             final contact = _resolveContact(connector);
             final showRecentPath = paths.isNotEmpty && contact.pathLength >= 0;
+            final unreadCount = connector.getUnreadCountForContactKey(widget.contact.publicKeyHex);
+            final unreadLabel = 'Unread: $unreadCount';
             return Column(
               crossAxisAlignment: CrossAxisAlignment.start,
               mainAxisSize: MainAxisSize.min,
@@ -53,19 +71,22 @@ class _ChatScreenState extends State<ChatScreen> {
                     behavior: HitTestBehavior.opaque,
                     onLongPress: () => _showFullPathDialog(context, paths.first.pathBytes),
                     child: Text(
-                      paths.first.displayText,
+                      '${paths.first.displayText} • $unreadLabel',
+                      overflow: TextOverflow.ellipsis,
                       style: const TextStyle(fontSize: 11, fontWeight: FontWeight.normal),
                     ),
                   )
                 else if (contact.pathLength >= 0)
                   Text(
-                    '${contact.pathLength} ${contact.pathLength == 1 ? 'hop' : 'hops'}',
+                    '${contact.pathLength} ${contact.pathLength == 1 ? 'hop' : 'hops'} • $unreadLabel',
+                    overflow: TextOverflow.ellipsis,
                     style: const TextStyle(fontSize: 11, fontWeight: FontWeight.normal),
                   )
                 else
-                  const Text(
-                    'No path',
-                    style: TextStyle(fontSize: 11, fontWeight: FontWeight.normal),
+                  Text(
+                    'No path • $unreadLabel',
+                    overflow: TextOverflow.ellipsis,
+                    style: const TextStyle(fontSize: 11, fontWeight: FontWeight.normal),
                   ),
               ],
             );
@@ -177,15 +198,15 @@ class _ChatScreenState extends State<ChatScreen> {
         return _MessageBubble(
           message: message,
           senderName: widget.contact.name,
-          onLongPress: message.isOutgoing && message.status == MessageStatus.failed
-              ? () => _showMessageRetry(context, message)
-              : null,
+          onTap: () => _openMessagePath(message),
+          onLongPress: () => _showMessageActions(message),
         );
       },
     );
   }
 
   Widget _buildInputBar(MeshCoreConnector connector) {
+    final maxBytes = maxContactMessageBytes();
     return Container(
       padding: const EdgeInsets.all(8),
       decoration: BoxDecoration(
@@ -231,6 +252,9 @@ class _ChatScreenState extends State<ChatScreen> {
 
                   return TextField(
                     controller: _textController,
+                    inputFormatters: [
+                      Utf8LengthLimitingTextInputFormatter(maxBytes),
+                    ],
                     decoration: const InputDecoration(
                       hintText: 'Type a message...',
                       border: OutlineInputBorder(),
@@ -275,6 +299,14 @@ class _ChatScreenState extends State<ChatScreen> {
     final text = _textController.text.trim();
     if (text.isEmpty) return;
 
+    final maxBytes = maxContactMessageBytes();
+    if (utf8.encode(text).length > maxBytes) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text('Message too long (max $maxBytes bytes).')),
+      );
+      return;
+    }
+
     connector.sendMessage(
       widget.contact,
       text,
@@ -543,30 +575,52 @@ class _ChatScreenState extends State<ChatScreen> {
   }
 
   void _showContactInfo(BuildContext context) {
+    final connector = Provider.of<MeshCoreConnector>(context, listen: false);
+    connector.ensureContactSmazSettingLoaded(widget.contact.publicKeyHex);
+
     showDialog(
       context: context,
-      builder: (context) => AlertDialog(
-        title: Text(widget.contact.name),
-        content: Column(
-          mainAxisSize: MainAxisSize.min,
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: [
-            _buildInfoRow('Type', widget.contact.typeLabel),
-            _buildInfoRow('Path', widget.contact.pathLabel),
-            if (widget.contact.hasLocation)
-              _buildInfoRow(
-                'Location',
-                '${widget.contact.latitude?.toStringAsFixed(4)}, ${widget.contact.longitude?.toStringAsFixed(4)}',
+      builder: (context) => Consumer<MeshCoreConnector>(
+        builder: (context, connector, _) {
+          final contact = _resolveContact(connector);
+          final smazEnabled = connector.isContactSmazEnabled(contact.publicKeyHex);
+
+          return AlertDialog(
+            title: Text(contact.name),
+            content: SingleChildScrollView(
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
+                crossAxisAlignment: CrossAxisAlignment.start,
+                children: [
+                  _buildInfoRow('Type', contact.typeLabel),
+                  _buildInfoRow('Path', contact.pathLabel),
+                  if (contact.hasLocation)
+                    _buildInfoRow(
+                      'Location',
+                      '${contact.latitude?.toStringAsFixed(4)}, ${contact.longitude?.toStringAsFixed(4)}',
+                    ),
+                  _buildInfoRow('Public Key', contact.publicKeyHex.substring(0, 16) + '...'),
+                  const Divider(),
+                  SwitchListTile(
+                    contentPadding: EdgeInsets.zero,
+                    title: const Text('SMAZ compression'),
+                    subtitle: const Text('Compress outgoing messages'),
+                    value: smazEnabled,
+                    onChanged: (value) {
+                      connector.setContactSmazEnabled(contact.publicKeyHex, value);
+                    },
+                  ),
+                ],
               ),
-            _buildInfoRow('Public Key', widget.contact.publicKeyHex.substring(0, 16) + '...'),
-          ],
-        ),
-        actions: [
-          TextButton(
-            onPressed: () => Navigator.pop(context),
-            child: const Text('Close'),
-          ),
-        ],
+            ),
+            actions: [
+              TextButton(
+                onPressed: () => Navigator.pop(context),
+                child: const Text('Close'),
+              ),
+            ],
+          );
+        },
       ),
     );
   }
@@ -940,27 +994,87 @@ class _ChatScreenState extends State<ChatScreen> {
     );
   }
 
-  void _showMessageRetry(BuildContext context, Message message) {
+  void _openMessagePath(Message message) {
+    final connector = context.read<MeshCoreConnector>();
+    final senderName =
+        message.isOutgoing ? (connector.selfName ?? 'Me') : widget.contact.name;
+    final pathMessage = ChannelMessage(
+      senderKey: null,
+      senderName: senderName,
+      text: message.text,
+      timestamp: message.timestamp,
+      isOutgoing: message.isOutgoing,
+      status: ChannelMessageStatus.sent,
+      repeatCount: 0,
+      pathLength: message.pathLength,
+      pathBytes: message.pathBytes,
+    );
+    Navigator.push(
+      context,
+      MaterialPageRoute(
+        builder: (context) => ChannelMessagePathScreen(message: pathMessage),
+      ),
+    );
+  }
+
+  void _showMessageActions(Message message) {
     showModalBottomSheet(
       context: context,
-      builder: (context) => SafeArea(
+      builder: (sheetContext) => SafeArea(
         child: Column(
           mainAxisSize: MainAxisSize.min,
           children: [
             ListTile(
-              leading: const Icon(Icons.refresh),
-              title: const Text('Retry'),
+              leading: const Icon(Icons.copy),
+              title: const Text('Copy'),
               onTap: () {
-                Navigator.pop(context);
-                _retryMessage(message);
+                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);
+              },
+            ),
+            if (message.isOutgoing && message.status == MessageStatus.failed)
+              ListTile(
+                leading: const Icon(Icons.refresh),
+                title: const Text('Retry'),
+                onTap: () {
+                  Navigator.pop(sheetContext);
+                  _retryMessage(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(Message message) async {
+    await context.read<MeshCoreConnector>().deleteMessage(message);
+    if (!mounted) return;
+    ScaffoldMessenger.of(context).showSnackBar(
+      const SnackBar(content: Text('Message deleted')),
+    );
+  }
+
   void _retryMessage(Message message) {
     final connector = Provider.of<MeshCoreConnector>(context, listen: false);
     connector.sendMessage(
@@ -977,11 +1091,13 @@ class _ChatScreenState extends State<ChatScreen> {
 class _MessageBubble extends StatelessWidget {
   final Message message;
   final String senderName;
+  final VoidCallback? onTap;
   final VoidCallback? onLongPress;
 
   const _MessageBubble({
     required this.message,
     required this.senderName,
+    this.onTap,
     this.onLongPress,
   });
 
@@ -1004,6 +1120,7 @@ class _MessageBubble extends StatelessWidget {
     return Padding(
       padding: const EdgeInsets.symmetric(vertical: 4),
       child: GestureDetector(
+        onTap: onTap,
         onLongPress: onLongPress,
         child: Row(
           mainAxisAlignment: isOutgoing ? MainAxisAlignment.end : MainAxisAlignment.start,
@@ -1176,10 +1293,6 @@ class _MessageBubble extends StatelessWidget {
     );
   }
 
-  String _formatPathPrefixes(Uint8List pathBytes) {
-    return pathBytes.map((b) => b.toRadixString(16).padLeft(2, '0')).join(',');
-  }
-
   Widget _buildAvatar(String senderName, ColorScheme colorScheme) {
     final initial = _getFirstCharacterOrEmoji(senderName);
     final color = _getColorForName(senderName);