feat(harness): improve trace fallback and reasoning audit

src/main/java/com/superbiz/agent/harness/guard/semantic/SemanticGuard.java

@@ -4,6 +4,8 @@ import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.superbiz.agent.harness.contract.SemanticVerdict;
+import com.superbiz.agent.harness.audit.DiagnosisTraceRecorder;
+import com.superbiz.agent.harness.audit.TraceAuditEvents;
 import com.superbiz.agent.harness.core.DiagnosisHarnessCore;
 import com.superbiz.agent.harness.core.RunContext;
 import com.superbiz.agent.harness.retry.HarnessRetryExecutor;
@@ -31,6 +33,7 @@ public final class SemanticGuard {
     private final ObjectMapper objectMapper;
     private final SemanticGuardLimits limits;
     private final Consumer<RetryAttempt> attemptRecorder;
+    private final DiagnosisTraceRecorder traceRecorder;
     private final String prompt;
 
     public SemanticGuard(DiagnosisHarnessCore core,
@@ -39,6 +42,17 @@ public final class SemanticGuard {
                          ObjectMapper objectMapper,
                          SemanticGuardLimits limits,
                          Consumer<RetryAttempt> attemptRecorder) {
+        this(core, retryExecutor, modelCall, objectMapper, limits,
+                attemptRecorder, DiagnosisTraceRecorder.noop());
+    }
+
+    public SemanticGuard(DiagnosisHarnessCore core,
+                         HarnessRetryExecutor retryExecutor,
+                         GuardModelCall modelCall,
+                         ObjectMapper objectMapper,
+                         SemanticGuardLimits limits,
+                         Consumer<RetryAttempt> attemptRecorder,
+                         DiagnosisTraceRecorder traceRecorder) {
         this.core = Objects.requireNonNull(core, "core must not be null");
         this.retryExecutor = Objects.requireNonNull(retryExecutor, "retryExecutor must not be null");
         this.modelCall = Objects.requireNonNull(modelCall, "modelCall must not be null");
@@ -46,6 +60,7 @@ public final class SemanticGuard {
         this.limits = Objects.requireNonNull(limits, "limits must not be null");
         this.attemptRecorder = Objects.requireNonNull(
                 attemptRecorder, "attemptRecorder must not be null");
+        this.traceRecorder = Objects.requireNonNull(traceRecorder, "traceRecorder must not be null");
         this.prompt = SemanticGuardPrompt.load();
     }
 
@@ -68,7 +83,10 @@ public final class SemanticGuard {
                 () -> parse(modelCall.call(
                         context, modelPrompt, remainingTimeout(startedNanos), limits.maxOutputBytes())),
                 this::classify,
-                attemptRecorder);
+                attempt -> {
+                    attemptRecorder.accept(attempt);
+                    traceRecorder.record(TraceAuditEvents.semanticAttempt(context, attempt));
+                });
     }
 
     private SemanticGuardDecision parse(String output) {