fix(#298): log path units truthfully instead of asserting wrong hop counts

The original diagnostic derived hops via realHopCount(), which divides a
value that firmware already defines as a hop count (src/Packet.h:79-84:
getPathByteLen() == getPathHashCount() * getPathHashSize()). It would have
reported hops=1 for a real 2-hop path, misleading the exact investigation
this logging exists to serve.

_pathDiag now reports the hop count directly and prints held-vs-implied
byte counts, flagging TRUNCATED when short. That makes the #309 decode
truncation self-evident in any capture without the device present.

The login dialogs no longer assert a hop count at all: selection.hopCount
is ambiguous by construction (device paths carry hops, user overrides carry
bytes, per #279), so they log the raw field, width and actual byte length,
which discriminates the two cases.

Refs #240, #279, #309

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/connector/meshcore_connector.dart

@@ -492,21 +492,30 @@ class MeshCoreConnector extends ChangeNotifier {
 
   int get pathHashByteWidth => _pathHashByteWidth;
 
-  /// Compact path rendering for logs: the raw byte length, the width it is
-  /// being sliced at, the resulting hop count, and the hop-grouped bytes.
+  /// Compact path rendering for logs: hop count, applied width, the bytes we
+  /// actually hold versus the bytes that hop count implies, and the hex.
   ///
-  /// Captures previously logged only the byte length, which made it impossible
-  /// to tell a single 2-byte hop from two 1-byte hops. That is the exact
-  /// question #240/#279 turn on. One line, existing log sites only, no new
-  /// per-frame logging. (#298)
-  String _pathDiag(List<int> pathBytes, int byteLen) {
-    if (byteLen < 0) return 'flood';
+  /// Captures previously logged only a length, which made it impossible to tell
+  /// a single 2-byte hop from two 1-byte hops. That is the exact question
+  /// #240/#279 turn on.
+  ///
+  /// [pathLenField] is the firmware path-len field's low 6 bits, which is a HOP
+  /// COUNT, not a byte length: firmware `src/Packet.h:79-84` defines
+  /// `getPathByteLen() == getPathHashCount() * getPathHashSize()`. Logging the
+  /// held byte count next to the implied one makes the #309 decode truncation
+  /// self-evident in any capture, without the device present.
+  ///
+  /// One line, existing log sites only, no new per-frame logging. (#298)
+  String _pathDiag(List<int> pathBytes, int pathLenField) {
+    if (pathLenField < 0) return 'flood';
     final w = _pathHashByteWidth;
-    final hops = realHopCount(byteLen, w);
-    final bytes = pathBytes.isEmpty
+    final expectedBytes = pathLenField * w;
+    final hex = pathBytes.isEmpty
         ? 'none'
         : PathHelper.formatPathHex(pathBytes, w);
-    return 'len=$byteLen w=$w hops=$hops [$bytes]';
+    final short = pathBytes.length < expectedBytes ? ' TRUNCATED' : '';
+    return 'hops=$pathLenField w=$w '
+        'bytes=${pathBytes.length}/$expectedBytes$short [$hex]';
   }
 
   CompanionRadioStats? get latestRadioStats => _latestRadioStats;

lib/widgets/repeater_login_dialog.dart

@@ -116,14 +116,18 @@ class _RepeaterLoginDialogState extends State<RepeaterLoginDialog> {
       );
       final timeoutSeconds = (timeoutMs / 1000).ceil();
       final timeout = Duration(milliseconds: timeoutMs + 2000);
-      // selection.hopCount is a BYTE count, not hops (#279). Log bytes, the
-      // applied width, the derived hop count and the hop-grouped bytes so a
-      // capture is unambiguous. (#298)
+      // `selection.hopCount` is ambiguous by construction: a device-discovered
+      // path carries a HOP count, a user override carries a BYTE count (#279).
+      // Do not assert hops here. Log the raw field, the width, and the actual
+      // byte length so a capture discriminates them:
+      //   bytes == field      -> byte-count semantics (override)
+      //   bytes == field * w  -> hop-count semantics (device)
+      // (#298)
       final routingWidth = _connector.pathHashByteWidth;
       final selectionLabel = selection.useFlood
           ? 'flood'
-          : 'bytes=${selection.hopCount} w=$routingWidth '
-                'hops=${realHopCount(selection.hopCount, routingWidth)} '
+          : 'field=${selection.hopCount} w=$routingWidth '
+                'bytes=${selection.pathBytes.length} '
                 '[${PathHelper.formatPathHex(selection.pathBytes, routingWidth)}]';
       appLogger.info('Login routing: $selectionLabel', tag: 'RepeaterLogin');
       bool? loginResult;

lib/widgets/room_login_dialog.dart

@@ -112,14 +112,18 @@ class _RoomLoginDialogState extends State<RoomLoginDialog> {
       );
       final timeoutSeconds = (timeoutMs / 1000).ceil();
       final timeout = Duration(milliseconds: timeoutMs + 2000);
-      // selection.hopCount is a BYTE count, not hops (#279). Log bytes, the
-      // applied width, the derived hop count and the hop-grouped bytes so a
-      // capture is unambiguous. (#298)
+      // `selection.hopCount` is ambiguous by construction: a device-discovered
+      // path carries a HOP count, a user override carries a BYTE count (#279).
+      // Do not assert hops here. Log the raw field, the width, and the actual
+      // byte length so a capture discriminates them:
+      //   bytes == field      -> byte-count semantics (override)
+      //   bytes == field * w  -> hop-count semantics (device)
+      // (#298)
       final routingWidth = _connector.pathHashByteWidth;
       final selectionLabel = selection.useFlood
           ? 'flood'
-          : 'bytes=${selection.hopCount} w=$routingWidth '
-                'hops=${realHopCount(selection.hopCount, routingWidth)} '
+          : 'field=${selection.hopCount} w=$routingWidth '
+                'bytes=${selection.pathBytes.length} '
                 '[${PathHelper.formatPathHex(selection.pathBytes, routingWidth)}]';
       appLogger.info('Login routing: $selectionLabel', tag: 'RoomLogin');
       bool? loginResult;