feat(otopcua): add ITagDiscovery.RediscoverPolicy + per-driver assignments (follow-up B)

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/ITagDiscovery.cs

@@ -1,5 +1,17 @@
 namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 
+/// <summary>How aggressively the host re-runs post-connect discovery for this driver.</summary>
+public enum DiscoveryRediscoverPolicy
+{
+    /// <summary>Retry every interval up to the cap or until the captured set is non-empty and stable
+    /// (for drivers whose discovered shape fills in asynchronously after connect, e.g. the FOCAS FixedTree).</summary>
+    UntilStable,
+    /// <summary>Run exactly one discovery pass on connect (drivers that discover synchronously in DiscoverAsync).</summary>
+    Once,
+    /// <summary>Never run post-connect discovery.</summary>
+    Never,
+}
+
 /// <summary>
 ///     Driver capability for discovering tags and hierarchy from the backend.
 ///     Streams discovered nodes into <see cref="IAddressSpaceBuilder"/> rather than
@@ -14,4 +26,7 @@ public interface ITagDiscovery
     /// <param name="builder">The address space builder to stream discovered nodes into.</param>
     /// <param name="cancellationToken">A cancellation token for the discovery operation.</param>
     Task DiscoverAsync(IAddressSpaceBuilder builder, CancellationToken cancellationToken);
+
+    /// <summary>Post-connect re-discovery policy. Default preserves the original retry-until-stable behavior.</summary>
+    DiscoveryRediscoverPolicy RediscoverPolicy => DiscoveryRediscoverPolicy.UntilStable;
 }