fix from copilot review + doc fix

documentation/routing-paths.md

@@ -15,6 +15,7 @@ The device capability determines the hash width (number of bytes per hop):
 | 1 byte | 256 | Single-byte node IDs |
 | 2 bytes | 65,536 | Medium meshes |
 | 3 bytes | 16.7M | Large networks |
+| 4 bytes | 4.3G | Very large meshes / future-proofing |
 
 ### Device Capability Detection
 
@@ -25,11 +26,11 @@ On device connection, the app reads the firmware capability to set `pathHashByte
 final modeRaw = firmwareBytes.length >= 82
     ? (firmwareBytes[81] & 0xFF)
     : 0;
-final mode = modeRaw.clamp(0, 2);
+final mode = modeRaw.clamp(0, 3);
-_pathHashByteWidth = mode + 1; // 1, 2, or 3 bytes per hop
+_pathHashByteWidth = mode + 1; // 1, 2, 3, or 4 bytes per hop
 ```
 
-The current implementation intentionally clamps to modes `0..2`, so the supported hop width is `1..3` bytes. Do not document 4-byte hops unless the connector implementation is widened first.
+The connector reads a single-mode byte and clamps to `0..3`, so the supported hop width is `1..4` bytes. UI code also clamps widths when rendering (typically to `1..4`) so 4-byte hops are handled end-to-end in the current codebase.
 
 ### Path Data Structure
 

lib/helpers/path_helper.dart

@@ -38,6 +38,7 @@ class PathHelper {
   /// - 1: Single byte per hop (256 unique nodes)
   /// - 2: Two bytes per hop (65K unique nodes)
   /// - 3: Three bytes per hop (16M unique nodes)
+  /// - 4: Four bytes per hop (4.3G unique nodes)
   static String resolvePathNames(
     List<int> pathBytes,
     List<Contact> allContacts,

lib/screens/channel_message_path_screen.dart

@@ -47,14 +47,12 @@ class ChannelMessagePathScreen extends StatelessWidget {
         final hops = _buildPathHops(primaryPath, connector, l10n, hashByteWidth);
         final hasHopDetails = primaryPath.isNotEmpty;
 
-        // Convert path byte length to hop count using the packet width.
+        // Convert observed path byte length to hop count using the packet width.
         // Legacy messages fall back to the current connector width.
+        // Reported path length (V3+) is already stored as a hop count; preserve
+        // the negative flood sentinel when present.
         final observedHopCount = _hopCountFromBytes(primaryPath.length, hashByteWidth);
-        final reportedHopCount = message.pathLength == null
+        final reportedHopCount = message.pathLength;
-          ? null
-          : (message.pathLength! < 0
-            ? message.pathLength
-            : _hopCountFromBytes(message.pathLength!, hashByteWidth));
         final effectiveHopCount = observedHopCount > 0
           ? observedHopCount
           : reportedHopCount;