chore(gateway): use ws bind as lock

src/gateway/server.test.ts

@@ -1,11 +1,9 @@
-import { randomUUID } from "node:crypto";
 import { type AddressInfo, createServer } from "node:net";
-import os from "node:os";
-import path from "node:path";
-import { afterEach, beforeEach, describe, expect, test, vi } from "vitest";
+import { describe, expect, test, vi } from "vitest";
 import { WebSocket } from "ws";
 import { emitAgentEvent } from "../infra/agent-events.js";
 import { startGatewayServer } from "./server.js";
+import { GatewayLockError } from "../infra/gateway-lock.js";
 
 vi.mock("../commands/health.js", () => ({
   getHealthSnapshot: vi.fn().mockResolvedValue({ ok: true, stub: true }),
@@ -27,19 +25,6 @@ vi.mock("../commands/agent.js", () => ({
 
 process.env.CLAWDIS_SKIP_PROVIDERS = "1";
 
-const originalLockPath = process.env.CLAWDIS_GATEWAY_LOCK_PATH;
-
-beforeEach(() => {
-  process.env.CLAWDIS_GATEWAY_LOCK_PATH = path.join(
-    os.tmpdir(),
-    `clawdis-gateway-${randomUUID()}.lock`,
-  );
-});
-
-afterEach(() => {
-  process.env.CLAWDIS_GATEWAY_LOCK_PATH = originalLockPath;
-});
-
 async function getFreePort(): Promise<number> {
   return await new Promise((resolve, reject) => {
     const server = createServer();
@@ -50,6 +35,17 @@ async function getFreePort(): Promise<number> {
   });
 }
 
+async function occupyPort(): Promise<{ server: ReturnType<typeof createServer>; port: number }> {
+  return await new Promise((resolve, reject) => {
+    const server = createServer();
+    server.once("error", reject);
+    server.listen(0, "127.0.0.1", () => {
+      const port = (server.address() as AddressInfo).port;
+      resolve({ server, port });
+    });
+  });
+}
+
 function onceMessage<T = unknown>(
   ws: WebSocket,
   filter: (obj: unknown) => boolean,
@@ -654,4 +650,12 @@ describe("gateway server", () => {
     ws.close();
     await server.close();
   });
+
+  test("refuses to start when port already bound", async () => {
+    const { server: blocker, port } = await occupyPort();
+    await expect(startGatewayServer(port)).rejects.toBeInstanceOf(
+      GatewayLockError,
+    );
+    blocker.close();
+  });
 });