feat(core-audit): wrap bound auditLog with TraceIdEnrichingAuditLog

bindAudit now wraps the inner sink/fan-out with TraceIdEnrichingAuditLog so
all sinks receive AuditEntry.correlationId auto-populated from the active
OTel span. bind-audit.test.ts assertions updated to check instanceof
TraceIdEnrichingAuditLog first, then .inner for the concrete sink type.
TraceIdEnrichingAuditLog exported from the package barrel.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-audit/src/di/bind-audit.test.ts

@@ -7,6 +7,7 @@ import { NoopAuditLog } from "../noop-audit-log";
 import { StdoutJsonAuditLog } from "../stdout-json-audit-log";
 import { PayloadAuditLog } from "../payload-audit-log";
 import { MultiSinkAuditLog } from "../multi-sink-audit-log";
+import { TraceIdEnrichingAuditLog } from "../trace-id-enriching-audit-log";
 import type { IAuditLog } from "../audit-log.interface";
 
 describe("bindAudit", () => {
@@ -14,28 +15,32 @@ describe("bindAudit", () => {
     const container = new Container();
     bindAudit(container, { payloadConfig: {} as never });
     const auditLog = container.get<IAuditLog>(AUDIT_SYMBOLS.IAuditLog);
-    expect(auditLog).toBeInstanceOf(MultiSinkAuditLog);
+    expect(auditLog).toBeInstanceOf(TraceIdEnrichingAuditLog);
+    expect((auditLog as unknown as { inner: unknown }).inner).toBeInstanceOf(MultiSinkAuditLog);
   });
 
   it("returns StdoutJsonAuditLog alone when payloadConfig omitted + default sinks", () => {
     const container = new Container();
     bindAudit(container, {});
     const auditLog = container.get<IAuditLog>(AUDIT_SYMBOLS.IAuditLog);
-    expect(auditLog).toBeInstanceOf(StdoutJsonAuditLog);
+    expect(auditLog).toBeInstanceOf(TraceIdEnrichingAuditLog);
+    expect((auditLog as unknown as { inner: unknown }).inner).toBeInstanceOf(StdoutJsonAuditLog);
   });
 
   it("returns NoopAuditLog when sinks=[]", () => {
     const container = new Container();
     bindAudit(container, { sinks: [] });
     const auditLog = container.get<IAuditLog>(AUDIT_SYMBOLS.IAuditLog);
-    expect(auditLog).toBeInstanceOf(NoopAuditLog);
+    expect(auditLog).toBeInstanceOf(TraceIdEnrichingAuditLog);
+    expect((auditLog as unknown as { inner: unknown }).inner).toBeInstanceOf(NoopAuditLog);
   });
 
   it("returns PayloadAuditLog when sinks=['payload'] only", () => {
     const container = new Container();
     bindAudit(container, { payloadConfig: {} as never, sinks: ["payload"] });
     const auditLog = container.get<IAuditLog>(AUDIT_SYMBOLS.IAuditLog);
-    expect(auditLog).toBeInstanceOf(PayloadAuditLog);
+    expect(auditLog).toBeInstanceOf(TraceIdEnrichingAuditLog);
+    expect((auditLog as unknown as { inner: unknown }).inner).toBeInstanceOf(PayloadAuditLog);
   });
 
   it("validates AUDIT_PSEUDONYM_SALT in production", () => {

packages/core-audit/src/di/bind-audit.ts

@@ -7,6 +7,7 @@ import { StdoutJsonAuditLog } from "../stdout-json-audit-log";
 import { MultiSinkAuditLog } from "../multi-sink-audit-log";
 import type { IAuditLog } from "../audit-log.interface";
 import { AUDIT_SYMBOLS } from "./symbols";
+import { TraceIdEnrichingAuditLog } from "../trace-id-enriching-audit-log";
 
 export type BindAuditOpts = {
   /** Payload config; required if "payload" is in sinks. */
@@ -25,8 +26,9 @@ export type BindAuditOpts = {
  * if not — better to refuse to start than to ship audit data with a dev-fallback
  * salt that an attacker could reverse.
  *
- * Note: Phase 4 wraps the returned auditLog in TraceIdEnrichingAuditLog
+ * The returned auditLog is wrapped in TraceIdEnrichingAuditLog (Phase 4)
- * for OTel correlation. Phase 2 returns the inner sink/fan-out directly.
+ * so all sinks receive AuditEntry.correlationId auto-populated from the
+ * active OTel span. The inner sink/fan-out is accessible via `.inner`.
  */
 export function bindAudit(
   container: Container,
@@ -49,10 +51,11 @@ export function bindAudit(
     sinks.push(new StdoutJsonAuditLog());
   }
 
-  const auditLog: IAuditLog =
+  const inner: IAuditLog =
     sinks.length > 1 ? new MultiSinkAuditLog(sinks)
     : sinks.length === 1 ? sinks[0]!
     : new NoopAuditLog();
+  const auditLog: IAuditLog = new TraceIdEnrichingAuditLog(inner);
 
   if (container.isBound(AUDIT_SYMBOLS.IAuditLog)) {
     container.unbind(AUDIT_SYMBOLS.IAuditLog);

packages/core-audit/src/index.ts

@@ -6,6 +6,7 @@ export { PayloadAuditLog } from "./payload-audit-log";
 export { MultiSinkAuditLog } from "./multi-sink-audit-log";
 export { auditLogsCollection } from "./audit-logs-collection";
 export { bindAudit, type BindAuditOpts } from "./di/bind-audit";
+export { TraceIdEnrichingAuditLog } from "./trace-id-enriching-audit-log";
 export { AUDIT_SYMBOLS } from "./di/symbols";
 // Phase 3 — GDPR erasure
 export { pseudonymize } from "./pseudonymize";