Auto: focas-f1d — Tool number + work coordinate offsets

Closes #260

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

@@ -112,6 +112,35 @@ internal static class FwlibNative
     [DllImport(Library, EntryPoint = "cnc_modal", ExactSpelling = true)]
     public static extern short Modal(ushort handle, short type, short block, ref ODBMDL buffer);
 
+    // ---- Tooling ----
+
+    /// <summary>
+    ///     <c>cnc_rdtnum</c> — read the currently selected tool number. Returns
+    ///     <c>EW_OK</c> + populates <see cref="IODBTNUM.Data"/> with the active T-code.
+    ///     Tool life + current offset index reads (<c>cnc_rdtlinfo</c>/<c>cnc_rdtlsts</c>/
+    ///     <c>cnc_rdtofs</c>) are deferred per the F1-d plan — those calls use ODBTLIFE*
+    ///     unions whose shape varies per series.
+    /// </summary>
+    [DllImport(Library, EntryPoint = "cnc_rdtnum", ExactSpelling = true)]
+    public static extern short RdToolNumber(ushort handle, ref IODBTNUM buffer);
+
+    // ---- Work coordinate offsets ----
+
+    /// <summary>
+    ///     <c>cnc_rdzofs</c> — read one work-coordinate offset slot. <paramref name="number"/>:
+    ///     1..6 = G54..G59 (standard). Extended <c>G54.1 P1..P48</c> use <c>cnc_rdzofsr</c>
+    ///     and are deferred. <paramref name="axis"/>: -1 = all axes returned, 1..N = single
+    ///     axis. <paramref name="length"/>: 12 + (N axes * 8) — we request -1 and let FWLIB
+    ///     fill up to <see cref="IODBZOFS.Data"/>'s 8-axis ceiling.
+    /// </summary>
+    [DllImport(Library, EntryPoint = "cnc_rdzofs", ExactSpelling = true)]
+    public static extern short RdWorkOffset(
+        ushort handle,
+        short number,
+        short axis,
+        short length,
+        ref IODBZOFS buffer);
+
     // ---- Structs ----
 
     /// <summary>
@@ -180,6 +209,38 @@ internal static class FwlibNative
         public byte[] Data;
     }
 
+    /// <summary>
+    ///     IODBTNUM — current tool number read buffer. <see cref="Data"/> holds the active
+    ///     T-code (Fanuc reference uses <c>long</c>; we narrow to <c>short</c> on the
+    ///     managed side because <see cref="FocasToolingInfo.CurrentTool"/> surfaces as
+    ///     <c>Int16</c>). Issue #260, F1-d.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Pack = 1)]
+    public struct IODBTNUM
+    {
+        public short Datano;
+        public short Type;
+        public int Data;
+    }
+
+    /// <summary>
+    ///     IODBZOFS — work-coordinate offset read buffer. 4-byte header + per-axis
+    ///     <c>OFSB</c> blocks (8 bytes each: 4-byte signed integer <c>data</c> + 2-byte
+    ///     <c>dec</c> decimal-point count + 2-byte <c>unit</c> + 2-byte <c>disp</c>).
+    ///     We marshal a fixed ceiling of 8 axes (= 64 bytes); the managed side reads
+    ///     only the first 3 (X / Y / Z) per the F1-d effort sizing.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential, Pack = 1)]
+    public struct IODBZOFS
+    {
+        public short Datano;
+        public short Type;
+        // Up to 8 axes * 8 bytes per OFSB = 64 bytes. Each block: int data, short dec,
+        // short unit, short disp (10 bytes per fwlib32.h). We size for the worst case.
+        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 80)]
+        public byte[] Data;
+    }
+
     /// <summary>ODBST — CNC status info. Machine state, alarm flags, automatic / edit mode.</summary>
     [StructLayout(LayoutKind.Sequential, Pack = 1)]
     public struct ODBST