fix(r2-10): breaker-close marker + IsBreakerOpen on ResilienceStatusSnapshot

src/Core/ZB.MOM.WW.OtOpcUa.Core/Resilience/DriverResilienceStatusTracker.cs

@@ -4,15 +4,19 @@ namespace ZB.MOM.WW.OtOpcUa.Core.Resilience;
 
 /// <summary>
 ///     Process-singleton tracker of live resilience counters per
-///     <c>(DriverInstanceId, HostName)</c>. Populated by the CapabilityInvoker and the
-///     MemoryTracking layer; consumed by a HostedService that periodically persists a
-///     snapshot to the <c>DriverInstanceResilienceStatus</c> table for Admin <c>/hosts</c>.
+///     <c>(DriverInstanceId, HostName)</c>. Populated by the CapabilityInvoker (call
+///     start/complete + success reset), the DriverResiliencePipelineBuilder's Polly
+///     telemetry (retry failure, breaker open/close), and the MemoryTracking layer
+///     (footprint). Read by <c>DriverResilienceStatusPublisherService</c> (Host, driver
+///     nodes) which periodically publishes each snapshot to the
+///     <c>driver-resilience-status</c> DistributedPubSub topic for the AdminUI
+///     resilience panel.
 /// </summary>
 /// <remarks>
-///     Per Phase 6.1 Stream E. No DB dependency here — the tracker is pure in-memory so
-///     tests can exercise it without EF Core or SQL Server. The HostedService that writes
-///     snapshots lives in the Server project (Stream E.2); the actual SignalR push + Blazor
-///     page refresh (E.3) lands in a follow-up visual-review PR.
+///     Pure in-memory (no EF Core / SQL Server dependency) so tests can exercise it directly.
+///     The operator-facing reader is the DPS publisher named above, mirroring the driver-health
+///     flow — not the DB-table/HostedService shape originally sketched for Phase 6.1 Stream E
+///     (R2-10 built the DPS reader instead).
 /// </remarks>
 public sealed class DriverResilienceStatusTracker
 {
@@ -62,6 +66,23 @@ public sealed class DriverResilienceStatusTracker
             (_, existing) => existing with { LastBreakerOpenUtc = utcNow, LastSampledUtc = utcNow });
     }
 
+    /// <summary>
+    ///     Record a circuit-breaker close (recovery) event — the paired counterpart to
+    ///     <see cref="RecordBreakerOpen"/>. Stamps <see cref="ResilienceStatusSnapshot.LastBreakerClosedUtc"/>
+    ///     so <see cref="ResilienceStatusSnapshot.IsBreakerOpen"/> can report whether the breaker
+    ///     is currently open. Called from the pipeline builder's <c>OnClosed</c> hook.
+    /// </summary>
+    /// <param name="driverInstanceId">The driver instance identifier.</param>
+    /// <param name="hostName">The host name.</param>
+    /// <param name="utcNow">The UTC timestamp of the breaker close event.</param>
+    public void RecordBreakerClose(string driverInstanceId, string hostName, DateTime utcNow)
+    {
+        var key = new StatusKey(driverInstanceId, hostName);
+        _status.AddOrUpdate(key,
+            _ => new ResilienceStatusSnapshot { LastBreakerClosedUtc = utcNow, LastSampledUtc = utcNow },
+            (_, existing) => existing with { LastBreakerClosedUtc = utcNow, LastSampledUtc = utcNow });
+    }
+
     /// <summary>Record a process recycle event (Tier C only).</summary>
     /// <param name="driverInstanceId">The driver instance identifier.</param>
     /// <param name="hostName">The host name.</param>
@@ -147,8 +168,21 @@ public sealed record ResilienceStatusSnapshot
     public int ConsecutiveFailures { get; init; }
     /// <summary>Gets the UTC timestamp of the last circuit-breaker open event, if any.</summary>
     public DateTime? LastBreakerOpenUtc { get; init; }
+    /// <summary>Gets the UTC timestamp of the last circuit-breaker close (recovery) event, if any.</summary>
+    public DateTime? LastBreakerClosedUtc { get; init; }
     /// <summary>Gets the UTC timestamp of the last recycle event, if any.</summary>
     public DateTime? LastRecycleUtc { get; init; }
+
+    /// <summary>
+    ///     Gets whether the circuit breaker is currently open for this (instance, host):
+    ///     an open event has been recorded and no later close event has superseded it.
+    ///     Note: Polly half-opens after <c>BreakDuration</c> without firing <c>OnClosed</c>
+    ///     (which fires only on a successful probe), so an idle driver can read "open" until
+    ///     the next call self-corrects it.
+    /// </summary>
+    public bool IsBreakerOpen =>
+        LastBreakerOpenUtc is { } open &&
+        (LastBreakerClosedUtc is not { } closed || open > closed);
     /// <summary>Gets the baseline process footprint in bytes.</summary>
     public long BaselineFootprintBytes { get; init; }
     /// <summary>Gets the current process footprint in bytes.</summary>