feat(audit): M5.3 response-capture increments — request headers, ceiling-hits counter, per-method body opt-out (T7)

1. Request headers in Extra JSON (AuditWriteMiddleware): adds a `requestHeaders`
   object to the existing Extra JSON alongside remoteIp/userAgent; headers whose
   names appear in AuditLogOptions.HeaderRedactList (Authorization, X-Api-Key,
   Cookie, Set-Cookie by default) are replaced with "<redacted>" using
   OrdinalIgnoreCase matching — same policy as ScadaBridgeAuditRedactor.

2. AuditInboundCeilingHits counter: new IAuditInboundCeilingHitsCounter interface
   + NoOpAuditInboundCeilingHitsCounter default; AuditCentralHealthSnapshot
   implements the interface (Interlocked field, thread-safe) and exposes
   AuditInboundCeilingHits on IAuditCentralHealthSnapshot; AddAuditLog registers
   the NoOp default, AddAuditLogCentralMaintenance forwards to the snapshot;
   AuditWriteMiddleware accepts the counter as an optional ctor arg and increments
   it once per request where either the request or response body hit the cap.

3. Per-method SkipBodyCapture opt-out: adds SkipBodyCapture bool to
   PerTargetRedactionOverride; AuditWriteMiddleware consults the per-target
   override map at the start of InvokeAsync (before EnableBuffering) and, when
   set, skips body read + capture entirely — the audit row still emits with
   headers/metadata but null RequestSummary/ResponseSummary; truncation flags
   are also cleared so the ceiling-hits counter is not bumped for opted-out methods.

tests/ZB.MOM.WW.ScadaBridge.AuditLog.Tests/Central/CentralAuditWriteFailuresTests.cs

@@ -8,6 +8,7 @@ using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Audit;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Audit;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
+using IAuditInboundCeilingHitsCounter = ZB.MOM.WW.ScadaBridge.AuditLog.Central.IAuditInboundCeilingHitsCounter;
 
 namespace ZB.MOM.WW.ScadaBridge.AuditLog.Tests.Central;
 
@@ -163,6 +164,69 @@ public class CentralAuditWriteFailuresTests : TestKit
         var snapshot = new AuditCentralHealthSnapshot();
         Assert.Equal(0, snapshot.CentralAuditWriteFailures);
         Assert.Equal(0, snapshot.AuditRedactionFailure);
+        Assert.Equal(0, snapshot.AuditInboundCeilingHits);
         Assert.Empty(snapshot.SiteAuditTelemetryStalled);
     }
+
+    // ---------------------------------------------------------------------
+    // M5.3 (T7) AuditInboundCeilingHits counter
+    // AuditCentralHealthSnapshot implements IAuditInboundCeilingHitsCounter.
+    // Incrementing through the interface surface is reflected on the snapshot.
+    // ---------------------------------------------------------------------
+
+    [Fact]
+    public void AuditInboundCeilingHits_StartsAtZero()
+    {
+        var snapshot = new AuditCentralHealthSnapshot();
+        Assert.Equal(0, snapshot.AuditInboundCeilingHits);
+    }
+
+    [Fact]
+    public void AuditInboundCeilingHits_IncrementedThroughInterface_ReflectedOnSnapshot()
+    {
+        var snapshot = new AuditCentralHealthSnapshot();
+        var counter = (IAuditInboundCeilingHitsCounter)snapshot;
+
+        counter.Increment();
+        counter.Increment();
+        counter.Increment();
+
+        Assert.Equal(3, snapshot.AuditInboundCeilingHits);
+    }
+
+    [Fact]
+    public void AuditInboundCeilingHits_IsThreadSafe()
+    {
+        // Interlocked increment must produce the correct count under concurrent
+        // increments — same shape as the existing counter tests.
+        var snapshot = new AuditCentralHealthSnapshot();
+        var counter = (IAuditInboundCeilingHitsCounter)snapshot;
+        const int incrementCount = 1000;
+
+        Parallel.For(0, incrementCount, _ => counter.Increment());
+
+        Assert.Equal(incrementCount, snapshot.AuditInboundCeilingHits);
+    }
+
+    [Fact]
+    public void AuditInboundCeilingHits_IsIndependentOfOtherCounters()
+    {
+        // Ceiling-hits increments must not cross-contaminate the other counters
+        // and vice versa — each Interlocked field is independent.
+        var snapshot = new AuditCentralHealthSnapshot();
+        var ceilingCounter = (IAuditInboundCeilingHitsCounter)snapshot;
+        var writeCounter = (ICentralAuditWriteFailureCounter)snapshot;
+        var redactCounter = (ZB.MOM.WW.ScadaBridge.AuditLog.Payload.IAuditRedactionFailureCounter)snapshot;
+
+        ceilingCounter.Increment();
+        ceilingCounter.Increment();
+        writeCounter.Increment();
+        redactCounter.Increment();
+        redactCounter.Increment();
+        redactCounter.Increment();
+
+        Assert.Equal(2, snapshot.AuditInboundCeilingHits);
+        Assert.Equal(1, snapshot.CentralAuditWriteFailures);
+        Assert.Equal(3, snapshot.AuditRedactionFailure);
+    }
 }