fix(driver-modbus-addressing): resolve Medium code-review finding (Driver.Modbus.Addressing-003)

Complete the incomplete Addressing-003 fix: TryParseByteOrder now produces a
diagnostic mentioning "field 2" when a known type-code token (e.g. BOOL) is
supplied in the byte-order slot, so the user is guided to the correct field.
The previous fix only wired the message in the else-branch, which was unreachable
because LooksLikeByteOrderToken(BOOL) returned true first.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing/ModbusAddressParser.cs

@@ -468,7 +468,14 @@ public static class ModbusAddressParser
 
         if ((int)order == -1)
         {
-            error = $"Unknown byte order '{text}'. Valid: ABCD, CDAB, BADC, DCBA";
+            // Driver.Modbus.Addressing-003: if the unknown token looks like a known type code
+            // (a 4-letter alphanumeric token that matches one of the recognised type strings),
+            // produce a diagnostic that directs the user to put the type in field 2, not field 3.
+            var isKnownTypeCode = text.ToUpperInvariant() is "BOOL" or "REAL" or "DINT" or "UINT"
+                || (text.Length <= 6 && text.StartsWith("STR", StringComparison.OrdinalIgnoreCase));
+            error = isKnownTypeCode
+                ? $"'{text}' looks like a type code; type belongs in field 2 (e.g. '40001:{text.ToUpperInvariant()}'), not field 3. Field 3 must be a 4-letter byte order (ABCD/CDAB/BADC/DCBA)"
+                : $"Unknown byte order '{text}'. Valid: ABCD, CDAB, BADC, DCBA";
             return false;
         }