fix(abcip): accept module-defined I/O tag paths (Local:1:I.Data, ABB_OmniCore:I.X)

Live read-only check: a production CompactLogix lists the module tag ABB_OmniCore:I in
@tags and libplctag reads ABB_OmniCore:I.ConnectionFaulted without complaint, but the
driver refused the path as malformed (identifier rule had no colon) and reported the
tag BadCommunicationError. Colon-separated identifier/slot parts are now legal in the
controller-scope base segment only (never past it, never under Program: scope).

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipTagPath.cs

@@ -100,7 +100,10 @@ public sealed record AbCipTagPath(
             var bracketIdx = part.IndexOf('[');
             if (bracketIdx < 0)
             {
-                if (!IsValidIdent(part)) return null;
+                // The controller-scope base name of a module-defined I/O tag carries colons
+                // (Local:1:I, ABB_OmniCore:I) — legal in the first segment only.
+                var isModuleBase = segments.Count == 0 && programScope is null && IsValidModuleBase(part);
+                if (!isModuleBase && !IsValidIdent(part)) return null;
                 segments.Add(new AbCipTagPathSegment(part, []));
                 continue;
             }
@@ -122,6 +125,25 @@ public sealed record AbCipTagPath(
         return new AbCipTagPath(programScope, segments, bitIndex);
     }
 
+    /// <summary>
+    ///     <c>true</c> for a module-defined I/O tag base name: an identifier followed by one or more
+    ///     <c>:</c>-separated identifier or slot-number parts (<c>Local:1:I</c>, <c>ABB_OmniCore:I</c>).
+    /// </summary>
+    /// <param name="s">The candidate base name.</param>
+    /// <returns><c>true</c> when <paramref name="s"/> is a module tag base name.</returns>
+    private static bool IsValidModuleBase(string s)
+    {
+        var parts = s.Split(':');
+        if (parts.Length < 2 || !IsValidIdent(parts[0])) return false;
+        for (var i = 1; i < parts.Length; i++)
+        {
+            var p = parts[i];
+            if (p.Length == 0) return false;
+            if (!IsValidIdent(p) && !p.All(char.IsAsciiDigit)) return false;
+        }
+        return true;
+    }
+
     private static bool IsValidIdent(string s)
     {
         if (string.IsNullOrEmpty(s)) return false;