chore: remove unused correlation middleware exports (#5333)

Verified dead-code removal: typecheck + tests + ESLint clean. Integrated into release/v3.8.41. Thanks @JxnLexn!

src/shared/middleware/correlationId.ts

@@ -41,58 +41,3 @@ export function runWithCorrelation(correlationId, fn) {
   const id = correlationId || generateCorrelationId();
   return correlationStore.run(id, fn);
 }
-
-/**
- * Express/Next.js middleware that injects correlation IDs.
- *
- * Usage:
- *   // In Next.js middleware or Express app
- *   import { correlationMiddleware } from './correlationId.js';
- *   app.use(correlationMiddleware);
- *
- * @param {Request} request
- * @param {Function} next
- * @returns {Promise<Response>}
- */
-export function correlationMiddleware(request, next) {
-  const requestId =
-    request.headers.get("x-request-id") ||
-    request.headers.get("x-correlation-id") ||
-    generateCorrelationId();
-
-  return runWithCorrelation(requestId, async () => {
-    const response = await next();
-
-    // Attach correlation ID to response
-    if (response && response.headers) {
-      response.headers.set("x-request-id", requestId);
-    }
-
-    return response;
-  });
-}
-
-/**
- * Create a logger wrapper that automatically includes correlation IDs.
- *
- * @param {Object} baseLogger - Base logger with info/warn/error methods
- * @returns {Object} Wrapped logger
- */
-export function createCorrelatedLogger(baseLogger) {
-  const withCorrelation = (level, ...args) => {
-    const correlationId = getCorrelationId();
-    if (correlationId) {
-      const meta = typeof args[args.length - 1] === "object" ? args.pop() : {};
-      meta.correlationId = correlationId;
-      args.push(meta);
-    }
-    baseLogger[level](...args);
-  };
-
-  return {
-    info: (...args) => withCorrelation("info", ...args),
-    warn: (...args) => withCorrelation("warn", ...args),
-    error: (...args) => withCorrelation("error", ...args),
-    debug: (...args) => withCorrelation("debug", ...args),
-  };
-}

tests/unit/observability-fase04.test.ts

@@ -171,7 +171,15 @@ test("requestTimeout: getProviderTimeout returns provider-specific value", () =>
 
 // ─── Correlation ID Tests ────────────────────────────
 
-import { getCorrelationId, runWithCorrelation } from "../../src/shared/middleware/correlationId.ts";
+import * as correlationId from "../../src/shared/middleware/correlationId.ts";
+const { getCorrelationId, runWithCorrelation } = correlationId;
+
+test("correlationId: public surface excludes unused wrapper helpers", () => {
+  assert.equal(Object.hasOwn(correlationId, "correlationMiddleware"), false);
+  assert.equal(Object.hasOwn(correlationId, "createCorrelatedLogger"), false);
+  assert.equal(typeof correlationId.getCorrelationId, "function");
+  assert.equal(typeof correlationId.runWithCorrelation, "function");
+});
 
 test("correlationId: getCorrelationId returns undefined outside context", () => {
   assert.equal(getCorrelationId(), undefined);