Auto: focas-f1f — figure scaling + diagnostics

Closes #262

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FwlibNative.cs

@@ -157,6 +157,25 @@ internal static class FwlibNative
         short length,
         ref OPMSG3 buffer);
 
+    // ---- Figure (per-axis decimal scaling) ----
+
+    /// <summary>
+    ///     <c>cnc_getfigure</c> — read per-axis figure info (decimal-place counts + units).
+    ///     <paramref name="kind"/>: 0 = absolute / relative / machine position figures,
+    ///     1 = work-coord shift figures (per Fanuc reference). The reply struct holds
+    ///     up to <see cref="MAX_AXIS"/> axis entries; the managed side reads the count
+    ///     out via <paramref name="outCount"/>. Position values from <c>cnc_absolute</c>
+    ///     / <c>cnc_machine</c> / <c>cnc_relative</c> / <c>cnc_distance</c> / <c>cnc_actf</c>
+    ///     are scaled integers — divide by <c>10^figureinfo[axis].dec</c> for user units
+    ///     (issue #262, plan PR F1-f).
+    /// </summary>
+    [DllImport(Library, EntryPoint = "cnc_getfigure", ExactSpelling = true)]
+    public static extern short GetFigure(
+        ushort handle,
+        short kind,
+        ref short outCount,
+        ref IODBAXIS figureinfo);
+
     // ---- Currently-executing block ----
 
     /// <summary>
@@ -298,6 +317,31 @@ internal static class FwlibNative
         public byte[] Data;
     }
 
+    /// <summary>
+    ///     Maximum axis count per the FWLIB <c>fwlib32.h</c> ceiling for figure-info reads.
+    ///     Real Fanuc CNCs cap at 8 simultaneous axes for most series; we marshal an
+    ///     8-entry array (matches <see cref="IODBAXIS"/>) so the call completes regardless
+    ///     of the deployment's axis count (issue #262).
+    /// </summary>
+    public const int MAX_AXIS = 8;
+
+    /// <summary>
+    ///     IODBAXIS — per-axis figure info read buffer for <c>cnc_getfigure</c>. Each
+    ///     axis entry carries the decimal-place count (<c>dec</c>) the CNC reports for
+    ///     that axis's increment system + a unit code. The managed side reads the first
+    ///     <c>outCount</c> entries returned by FWLIB; we marshal a fixed 8-entry ceiling
+    ///     (issue #262, plan PR F1-f).
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Pack = 1)]
+    public struct IODBAXIS
+    {
+        // Each entry per fwlib32.h is { short dec, short unit, short reserved, short reserved2 }
+        // = 8 bytes. 8 axes * 8 bytes = 64 bytes; we marshal a fixed byte buffer + decode on
+        // the managed side so axis-count growth doesn't churn the P/Invoke surface.
+        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 8 * 8)]
+        public byte[] Data;
+    }
+
     /// <summary>ODBST — CNC status info. Machine state, alarm flags, automatic / edit mode.</summary>
     [StructLayout(LayoutKind.Sequential, Pack = 1)]
     public struct ODBST