Auto: focas-f1e — operator messages + block text

Closes #261

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

@@ -114,6 +114,27 @@ public interface IFocasClient : IDisposable
     /// </summary>
     Task<FocasWorkOffsetsInfo?> GetWorkOffsetsAsync(CancellationToken cancellationToken)
         => Task.FromResult<FocasWorkOffsetsInfo?>(null);
+
+    /// <summary>
+    ///     Read the four FANUC operator-message classes via <c>cnc_rdopmsg3</c> (issue #261).
+    ///     The call returns up to 4 active messages per class; the driver collapses the
+    ///     latest non-empty message per class onto the <c>Messages/External/Latest</c>
+    ///     fixed-tree node — the issue body permits this minimal surface in the first cut.
+    ///     Trailing nulls / spaces are trimmed before publishing so the same message
+    ///     round-trips with stable text. Returns <c>null</c> when the wire client cannot
+    ///     supply the snapshot (older transport variant).
+    /// </summary>
+    Task<FocasOperatorMessagesInfo?> GetOperatorMessagesAsync(CancellationToken cancellationToken)
+        => Task.FromResult<FocasOperatorMessagesInfo?>(null);
+
+    /// <summary>
+    ///     Read the currently-executing block text via <c>cnc_rdactpt</c> (issue #261).
+    ///     The call returns the active block of the running program; surfaced as
+    ///     <c>Program/CurrentBlock</c> Float-trimmed string. Returns <c>null</c> when the
+    ///     wire client cannot supply the snapshot.
+    /// </summary>
+    Task<FocasCurrentBlockInfo?> GetCurrentBlockAsync(CancellationToken cancellationToken)
+        => Task.FromResult<FocasCurrentBlockInfo?>(null);
 }
 
 /// <summary>
@@ -215,6 +236,35 @@ public sealed record FocasWorkOffset(string Name, double X, double Y, double Z);
 /// </summary>
 public sealed record FocasWorkOffsetsInfo(IReadOnlyList<FocasWorkOffset> Offsets);
 
+/// <summary>
+///     One FANUC operator message — the <see cref="Number"/> + <see cref="Class"/>
+///     + <see cref="Text"/> tuple returned by <c>cnc_rdopmsg3</c> for a single
+///     active message slot. <see cref="Class"/> is one of <c>"OPMSG"</c> /
+///     <c>"MACRO"</c> / <c>"EXTERN"</c> / <c>"REJ-EXT"</c> per the FOCAS reference
+///     for the four message types. <see cref="Text"/> is trimmed of trailing
+///     nulls + spaces so round-trips through the OPC UA address space stay stable
+///     (issue #261).
+/// </summary>
+public sealed record FocasOperatorMessage(short Number, string Class, string Text);
+
+/// <summary>
+///     Snapshot of all active FANUC operator messages across the four message
+///     classes (issue #261). Surfaced under the FOCAS driver's
+///     <c>Messages/External/Latest</c> fixed-tree node — the latest non-empty
+///     message in the list is what gets published. Empty list means the CNC
+///     reported no active messages; the node publishes an empty string in that
+///     case.
+/// </summary>
+public sealed record FocasOperatorMessagesInfo(IReadOnlyList<FocasOperatorMessage> Messages);
+
+/// <summary>
+///     Snapshot of the currently-executing program block text via
+///     <c>cnc_rdactpt</c> (issue #261). <see cref="Text"/> is trimmed of trailing
+///     nulls + spaces so the same block round-trips with stable text. Surfaced
+///     as a String node at <c>Program/CurrentBlock</c>.
+/// </summary>
+public sealed record FocasCurrentBlockInfo(string Text);
+
 /// <summary>Factory for <see cref="IFocasClient"/>s. One client per configured device.</summary>
 public interface IFocasClientFactory
 {