Phase 6.1 Stream E (data layer) — DriverInstanceResilienceStatus entity + DriverResilienceStatusTracker + EF migration

Ships the data + runtime layer of Stream E. The SignalR hub and Blazor /hosts
page refresh (E.2-E.3) are follow-up work paired with the visual-compliance
review per Phase 6.4 patterns — documented as a deferred follow-up below.

Configuration:
- New entity DriverInstanceResilienceStatus with:
  DriverInstanceId, HostName (composite PK),
  LastCircuitBreakerOpenUtc, ConsecutiveFailures, CurrentBulkheadDepth,
  LastRecycleUtc, BaselineFootprintBytes, CurrentFootprintBytes,
  LastSampledUtc.
- Separate from DriverHostStatus (per-host connectivity view) so a Running
  host that has tripped its breaker or is nearing its memory ceiling shows up
  distinctly on Admin /hosts. Admin page left-joins both for display.
- OtOpcUaConfigDbContext + Fluent-API config + IX_DriverResilience_LastSampled
  index for the stale-sample filter query.
- EF migration: 20260419124034_AddDriverInstanceResilienceStatus.

Core.Resilience:
- DriverResilienceStatusTracker — process-singleton in-memory tracker keyed on
  (DriverInstanceId, HostName). CapabilityInvoker + MemoryTracking +
  MemoryRecycle callers record failure/success/breaker-open/recycle/footprint
  events; a HostedService (Stream E.2 follow-up) samples this tracker every
  5 s and persists to the DB. Pure in-memory keeps tests fast + the core
  free of EF/SQL dependencies.

Tests:
- DriverResilienceStatusTrackerTests (9 new, all pass): tryget-before-write
  returns null; failures accumulate; success resets; breaker/recycle/footprint
  fields populate; per-host isolation; snapshot returns all pairs; concurrent
  writes don't lose counts.
- SchemaComplianceTests: expected-tables list updated to include the new
  DriverInstanceResilienceStatus table.

Full solution dotnet test: 1042 passing (baseline 906, +136 for Phase 6.1 so
far across Streams A/B/C/D/E.1). Pre-existing Client.CLI Subscribe flake
unchanged.

Deferred to follow-up PR (E.2/E.3):
- ResilienceStatusPublisher HostedService that samples DriverResilienceStatusTracker
  every 5 s + upserts DriverInstanceResilienceStatus rows.
- Admin FleetStatusHub SignalR hub pushing LastCircuitBreakerOpenUtc /
  CurrentBulkheadDepth / LastRecycleUtc on change.
- Admin /hosts Blazor column additions (red badge when
  ConsecutiveFailures > breakerThreshold / 2). Visual-compliance reviewer
  signoff alongside Phase 6.4 admin-ui patterns.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/ZB.MOM.WW.OtOpcUa.Core.Tests/Resilience/DriverResilienceStatusTrackerTests.cs

@@ -0,0 +1,110 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Resilience;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.Tests.Resilience;
+
+[Trait("Category", "Unit")]
+public sealed class DriverResilienceStatusTrackerTests
+{
+    private static readonly DateTime Now = new(2026, 4, 19, 12, 0, 0, DateTimeKind.Utc);
+
+    [Fact]
+    public void TryGet_Returns_Null_Before_AnyWrite()
+    {
+        var tracker = new DriverResilienceStatusTracker();
+
+        tracker.TryGet("drv", "host").ShouldBeNull();
+    }
+
+    [Fact]
+    public void RecordFailure_Accumulates_ConsecutiveFailures()
+    {
+        var tracker = new DriverResilienceStatusTracker();
+
+        tracker.RecordFailure("drv", "host", Now);
+        tracker.RecordFailure("drv", "host", Now.AddSeconds(1));
+        tracker.RecordFailure("drv", "host", Now.AddSeconds(2));
+
+        tracker.TryGet("drv", "host")!.ConsecutiveFailures.ShouldBe(3);
+    }
+
+    [Fact]
+    public void RecordSuccess_Resets_ConsecutiveFailures()
+    {
+        var tracker = new DriverResilienceStatusTracker();
+        tracker.RecordFailure("drv", "host", Now);
+        tracker.RecordFailure("drv", "host", Now.AddSeconds(1));
+
+        tracker.RecordSuccess("drv", "host", Now.AddSeconds(2));
+
+        tracker.TryGet("drv", "host")!.ConsecutiveFailures.ShouldBe(0);
+    }
+
+    [Fact]
+    public void RecordBreakerOpen_Populates_LastBreakerOpenUtc()
+    {
+        var tracker = new DriverResilienceStatusTracker();
+
+        tracker.RecordBreakerOpen("drv", "host", Now);
+
+        tracker.TryGet("drv", "host")!.LastBreakerOpenUtc.ShouldBe(Now);
+    }
+
+    [Fact]
+    public void RecordRecycle_Populates_LastRecycleUtc()
+    {
+        var tracker = new DriverResilienceStatusTracker();
+
+        tracker.RecordRecycle("drv", "host", Now);
+
+        tracker.TryGet("drv", "host")!.LastRecycleUtc.ShouldBe(Now);
+    }
+
+    [Fact]
+    public void RecordFootprint_CapturesBaselineAndCurrent()
+    {
+        var tracker = new DriverResilienceStatusTracker();
+
+        tracker.RecordFootprint("drv", "host", baselineBytes: 100_000_000, currentBytes: 150_000_000, Now);
+
+        var snap = tracker.TryGet("drv", "host")!;
+        snap.BaselineFootprintBytes.ShouldBe(100_000_000);
+        snap.CurrentFootprintBytes.ShouldBe(150_000_000);
+    }
+
+    [Fact]
+    public void DifferentHosts_AreIndependent()
+    {
+        var tracker = new DriverResilienceStatusTracker();
+
+        tracker.RecordFailure("drv", "host-a", Now);
+        tracker.RecordFailure("drv", "host-b", Now);
+        tracker.RecordSuccess("drv", "host-a", Now.AddSeconds(1));
+
+        tracker.TryGet("drv", "host-a")!.ConsecutiveFailures.ShouldBe(0);
+        tracker.TryGet("drv", "host-b")!.ConsecutiveFailures.ShouldBe(1);
+    }
+
+    [Fact]
+    public void Snapshot_ReturnsAll_TrackedPairs()
+    {
+        var tracker = new DriverResilienceStatusTracker();
+        tracker.RecordFailure("drv-1", "host-a", Now);
+        tracker.RecordFailure("drv-1", "host-b", Now);
+        tracker.RecordFailure("drv-2", "host-a", Now);
+
+        var snapshot = tracker.Snapshot();
+
+        snapshot.Count.ShouldBe(3);
+    }
+
+    [Fact]
+    public void ConcurrentWrites_DoNotLose_Failures()
+    {
+        var tracker = new DriverResilienceStatusTracker();
+        Parallel.For(0, 500, _ => tracker.RecordFailure("drv", "host", Now));
+
+        tracker.TryGet("drv", "host")!.ConsecutiveFailures.ShouldBe(500);
+    }
+}