fix(gateway): keep tearing down listeners when cron.stopAndDrain() rejects on shutdown (#114848)

The close handler ran cron.stopAndDrain() and heartbeatRunner.stop() bare, while every sibling
teardown uses shutdownStep() (catch/warn/continue). stopAndDrain() re-throws stream-watcher stop
failures by design, so the rejection skipped the remaining teardown -- wss.close(), httpServer.close(),
client closes, interval clears -- leaving the port bound and timers live; the next listen() then hits
EADDRINUSE. Wrap both calls in shutdownStep. Adds a regression test.

Co-authored-by: MatthewSynthia <matthewsynthia@users.noreply.github.com>

src/gateway/server-close.test.ts

@@ -182,6 +182,26 @@ describe("createGatewayCloseHandler", () => {
     }
   });
 
+  it("still runs later teardown when cron.stopAndDrain() rejects (no listener strand)", async () => {
+    const stopAndDrain = vi.fn().mockRejectedValue(new Error("stream watcher stop failed"));
+    const httpClose = vi.fn((cb: (err?: Error | null) => void) => cb(null));
+    const deps = createGatewayCloseTestDeps({
+      cron: { stop: vi.fn(), stopAndDrain } as never,
+      httpServer: { close: httpClose, closeIdleConnections: vi.fn() } as never,
+    });
+    const close = createGatewayCloseHandler(deps);
+
+    const result = await close({ reason: "test" });
+
+    // A rejecting stopAndDrain must be swallowed (recorded as a warning) and must NOT skip the
+    // remaining teardown -- otherwise the HTTP/WS listeners and timers strand and the next
+    // start hits EADDRINUSE.
+    expect(stopAndDrain).toHaveBeenCalledTimes(1);
+    expect(deps.heartbeatRunner.stop).toHaveBeenCalledTimes(1);
+    expect(httpClose).toHaveBeenCalled();
+    expect(result.warnings.length).toBeGreaterThan(0);
+  });
+
   it("completes a clean shutdown with a ShutdownResult", async () => {
     const deps = createGatewayCloseTestDeps();
     const close = createGatewayCloseHandler(deps);

src/gateway/server-close.ts

@@ -883,12 +883,12 @@ export function createGatewayCloseHandler(
       await measureCloseStep("gmail-watcher", () =>
         shutdownStep("gmail-watcher", () => stopGmailWatcherOnDemand(), warnings),
       );
-      if (params.cron.stopAndDrain) {
-        await params.cron.stopAndDrain();
-      } else {
-        params.cron.stop();
-      }
-      params.heartbeatRunner.stop();
+      await shutdownStep(
+        "cron",
+        () => (params.cron.stopAndDrain ? params.cron.stopAndDrain() : params.cron.stop()),
+        warnings,
+      );
+      await shutdownStep("heartbeat-runner", () => params.heartbeatRunner.stop(), warnings);
       await shutdownStep(
         "task-registry-maintenance",
         () => params.stopTaskRegistryMaintenance?.(),