fix(dcl): ASCII-only connection actor names, guarded ActorOf, and gate rejection of colliding connection names (review 2026-10-21 lane A M2)

ConnectionActorNames.Sanitize (shared by the DCL manager and the site deploy
gate) keeps ASCII letters/digits and -_.*+:@&=,!~';() only. The manager fails a
connection whose sanitised name is invalid or already used (Error + site
event) instead of restarting; DeployCompileValidator rejects a config whose
connection names collide after sanitising.

src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/ConnectionActorNames.cs

@@ -0,0 +1,43 @@
+namespace ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Actors;
+
+/// <summary>
+/// Maps a data connection name to the Akka actor name of its <see cref="DataConnectionActor"/>
+/// (review 2026-10-21, lane A M2). Shared by <see cref="DataConnectionManagerActor"/> (which
+/// creates the actor) and the site deploy gate (which rejects a config whose connection names
+/// would collide once sanitised), so both always agree on the name.
+///
+/// <para>
+/// Every output is a legal Akka path element: ASCII letters and digits plus
+/// <c>-_.*+:@&amp;=,!~';()</c> are kept, everything else — spaces, <c>/</c>, <c>#</c>, <c>$</c>
+/// and every non-ASCII character — becomes <c>-</c>. The previous sanitiser kept
+/// <see cref="char.IsLetterOrDigit(char)"/> (true for non-ASCII letters, which Akka refuses) and
+/// <c>$</c> (refused as a leading character), so "Ofen Süd" or "$PLC" threw out of
+/// <c>Context.ActorOf</c>. The mapping is NOT injective ("PLC A" and "PLC-A" both give
+/// "PLC-A"); callers must treat a collision as an error for the later connection.
+/// </para>
+/// </summary>
+public static class ConnectionActorNames
+{
+    private const string KeptSymbols = "-_.*+:@&=,!~';()";
+
+    /// <summary>The actor name used for <paramref name="connectionName"/>.</summary>
+    /// <param name="connectionName">The data connection's configured name.</param>
+    /// <returns>A legal, non-empty Akka actor name.</returns>
+    public static string Sanitize(string connectionName)
+    {
+        if (string.IsNullOrEmpty(connectionName))
+            return "-";
+
+        var chars = new char[connectionName.Length];
+        for (var i = 0; i < chars.Length; i++)
+        {
+            var c = connectionName[i];
+            chars[i] = (c is >= 'a' and <= 'z' or >= 'A' and <= 'Z' or >= '0' and <= '9') ||
+                       KeptSymbols.Contains(c)
+                ? c
+                : '-';
+        }
+
+        return new string(chars);
+    }
+}