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>

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

@@ -0,0 +1,104 @@
+using System.Collections.Concurrent;
+
+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>.
+/// </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.
+/// </remarks>
+public sealed class DriverResilienceStatusTracker
+{
+    private readonly ConcurrentDictionary<StatusKey, ResilienceStatusSnapshot> _status = new();
+
+    /// <summary>Record a Polly pipeline failure for <paramref name="hostName"/>.</summary>
+    public void RecordFailure(string driverInstanceId, string hostName, DateTime utcNow)
+    {
+        var key = new StatusKey(driverInstanceId, hostName);
+        _status.AddOrUpdate(key,
+            _ => new ResilienceStatusSnapshot { ConsecutiveFailures = 1, LastSampledUtc = utcNow },
+            (_, existing) => existing with
+            {
+                ConsecutiveFailures = existing.ConsecutiveFailures + 1,
+                LastSampledUtc = utcNow,
+            });
+    }
+
+    /// <summary>Reset the consecutive-failure count on a successful pipeline execution.</summary>
+    public void RecordSuccess(string driverInstanceId, string hostName, DateTime utcNow)
+    {
+        var key = new StatusKey(driverInstanceId, hostName);
+        _status.AddOrUpdate(key,
+            _ => new ResilienceStatusSnapshot { ConsecutiveFailures = 0, LastSampledUtc = utcNow },
+            (_, existing) => existing with
+            {
+                ConsecutiveFailures = 0,
+                LastSampledUtc = utcNow,
+            });
+    }
+
+    /// <summary>Record a circuit-breaker open event.</summary>
+    public void RecordBreakerOpen(string driverInstanceId, string hostName, DateTime utcNow)
+    {
+        var key = new StatusKey(driverInstanceId, hostName);
+        _status.AddOrUpdate(key,
+            _ => new ResilienceStatusSnapshot { LastBreakerOpenUtc = utcNow, LastSampledUtc = utcNow },
+            (_, existing) => existing with { LastBreakerOpenUtc = utcNow, LastSampledUtc = utcNow });
+    }
+
+    /// <summary>Record a process recycle event (Tier C only).</summary>
+    public void RecordRecycle(string driverInstanceId, string hostName, DateTime utcNow)
+    {
+        var key = new StatusKey(driverInstanceId, hostName);
+        _status.AddOrUpdate(key,
+            _ => new ResilienceStatusSnapshot { LastRecycleUtc = utcNow, LastSampledUtc = utcNow },
+            (_, existing) => existing with { LastRecycleUtc = utcNow, LastSampledUtc = utcNow });
+    }
+
+    /// <summary>Capture / update the MemoryTracking-supplied baseline + current footprint.</summary>
+    public void RecordFootprint(string driverInstanceId, string hostName, long baselineBytes, long currentBytes, DateTime utcNow)
+    {
+        var key = new StatusKey(driverInstanceId, hostName);
+        _status.AddOrUpdate(key,
+            _ => new ResilienceStatusSnapshot
+            {
+                BaselineFootprintBytes = baselineBytes,
+                CurrentFootprintBytes = currentBytes,
+                LastSampledUtc = utcNow,
+            },
+            (_, existing) => existing with
+            {
+                BaselineFootprintBytes = baselineBytes,
+                CurrentFootprintBytes = currentBytes,
+                LastSampledUtc = utcNow,
+            });
+    }
+
+    /// <summary>Snapshot of a specific (instance, host) pair; null if no counters recorded yet.</summary>
+    public ResilienceStatusSnapshot? TryGet(string driverInstanceId, string hostName) =>
+        _status.TryGetValue(new StatusKey(driverInstanceId, hostName), out var snapshot) ? snapshot : null;
+
+    /// <summary>Copy of every currently-tracked (instance, host, snapshot) triple. Safe under concurrent writes.</summary>
+    public IReadOnlyList<(string DriverInstanceId, string HostName, ResilienceStatusSnapshot Snapshot)> Snapshot() =>
+        _status.Select(kvp => (kvp.Key.DriverInstanceId, kvp.Key.HostName, kvp.Value)).ToList();
+
+    private readonly record struct StatusKey(string DriverInstanceId, string HostName);
+}
+
+/// <summary>Snapshot of the resilience counters for one <c>(DriverInstanceId, HostName)</c> pair.</summary>
+public sealed record ResilienceStatusSnapshot
+{
+    public int ConsecutiveFailures { get; init; }
+    public DateTime? LastBreakerOpenUtc { get; init; }
+    public DateTime? LastRecycleUtc { get; init; }
+    public long BaselineFootprintBytes { get; init; }
+    public long CurrentFootprintBytes { get; init; }
+    public DateTime LastSampledUtc { get; init; }
+}