fix(focas): serialize per-device wire I/O + bound reads; tolerate AdminUI config formats

Equipment tags were stuck at Bad_WaitingForInitialData on the deployed driver: the equipment poll, fixed-tree loop, probe and recycle shared one FOCAS/2 socket with no serialization, and the steady-state read had no timeout — concurrent reads collided and a stalled read hung forever, never overwriting the node's initial-data seed.

- SynchronizedFocasClient: per-device SemaphoreSlim gate + per-call timeout around every wire op (Connect/Probe gated, not double-bounded); wired in EnsureConnectedAsync. ReadAsync/WriteAsync map a per-call timeout to BadCommunicationError instead of rethrowing.
- FlexibleStringConverter on FOCAS config Series: the AdminUI persists the enum as a number ("series":6); accept number-or-string instead of throwing -> stub.
- FocasHostAddress.TryParse tolerates a scheme-less {ip}[:{port}] (AdminUI hostAddress form); canonical focas:// unchanged, malformed schemes still rejected.

247 FOCAS tests green; each fix has a regression test. Live-validated on wonder-app-vd03 (tags read Good).

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasDriverFactoryExtensions.cs

@@ -195,12 +195,41 @@ public static class FocasDriverFactoryExtensions
         AllowTrailingCommas = true,
     };
 
+    /// <summary>
+    ///     Reads a JSON property as a string, tolerating a JSON <b>number</b> token as well. The
+    ///     AdminUI persists the FOCAS <c>Series</c> enum as its integer value (e.g. <c>"series":6</c>),
+    ///     while this DTO models <c>Series</c> as a string handed to <see cref="ParseSeries"/>
+    ///     (Enum.TryParse accepts the numeric form). Without this, System.Text.Json throws
+    ///     "Cannot get the value of a token type 'Number' as a string" on the bare number and the
+    ///     driver falls back to a stub. Accepts string / number / null and emits a string.
+    /// </summary>
+    internal sealed class FlexibleStringConverter : JsonConverter<string?>
+    {
+        public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) =>
+            reader.TokenType switch
+            {
+                JsonTokenType.String => reader.GetString(),
+                JsonTokenType.Number => reader.TryGetInt64(out var n)
+                    ? n.ToString(System.Globalization.CultureInfo.InvariantCulture)
+                    : reader.GetDouble().ToString(System.Globalization.CultureInfo.InvariantCulture),
+                JsonTokenType.Null => null,
+                _ => throw new JsonException($"Expected string, number, or null but got {reader.TokenType}."),
+            };
+
+        public override void Write(Utf8JsonWriter writer, string? value, JsonSerializerOptions options)
+        {
+            if (value is null) writer.WriteNullValue();
+            else writer.WriteStringValue(value);
+        }
+    }
+
     internal sealed class FocasDriverConfigDto
     {
         /// <summary>Gets or sets the FOCAS client factory backend name (e.g. "wire" or "stub").</summary>
         public string? Backend { get; init; }
 
         /// <summary>Gets or sets the CNC series for this driver.</summary>
+        [JsonConverter(typeof(FlexibleStringConverter))]
         public string? Series { get; init; }
 
         /// <summary>Gets or sets the operation timeout in milliseconds.</summary>
@@ -234,6 +263,7 @@ public static class FocasDriverFactoryExtensions
         public string? DeviceName { get; init; }
 
         /// <summary>Gets or sets the CNC series for this device (overrides top-level series if provided).</summary>
+        [JsonConverter(typeof(FlexibleStringConverter))]
         public string? Series { get; init; }
 
         /// <summary>