feat(focas): scale axis positions by 10^PositionDecimalPlaces (config-supplied)

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Contracts/FocasDriverOptions.cs

@@ -109,10 +109,27 @@ public sealed class FocasAlarmProjectionOptions
 ///     address validation at <c>FocasDriver.InitializeAsync</c>; leave as
 ///     <see cref="FocasCncSeries.Unknown"/> to skip validation (legacy behaviour).
 /// </summary>
+/// <param name="PositionDecimalPlaces">
+///     Axis positions returned by <c>cnc_rddynamic2</c> are scaled integers. The driver
+///     divides AbsolutePosition / MachinePosition / RelativePosition / DistanceToGo by
+///     <c>10^PositionDecimalPlaces</c> at the publish seam so they surface in engineering
+///     units on the Float64 axis nodes. Default <c>0</c> (no scaling) is byte-identical to
+///     legacy behaviour. Auto-fetching this via <c>cnc_getfigure</c> is deferred (wire-gated),
+///     so it is config-supplied. Negative values are clamped to 0 (no scaling).
+/// </param>
 public sealed record FocasDeviceOptions(
     string HostAddress,
     string? DeviceName = null,
-    FocasCncSeries Series = FocasCncSeries.Unknown);
+    FocasCncSeries Series = FocasCncSeries.Unknown,
+    int PositionDecimalPlaces = 0)
+{
+    /// <summary>
+    ///     Axis-position decimal places, clamped to a non-negative value so the
+    ///     <c>10^PositionDecimalPlaces</c> divide at the publish seam can never misbehave.
+    /// </summary>
+    public int PositionDecimalPlaces { get; init; } =
+        PositionDecimalPlaces < 0 ? 0 : PositionDecimalPlaces;
+}
 
 /// <summary>
 ///     One FOCAS-backed OPC UA variable. <paramref name="Address"/> is the canonical FOCAS