fix: add close() lifecycle methods to all adapters, fix WS client handler preservation, add Worker thread context guard

- Add close() to Redis, WS Client, WS Server, Worker Host, Worker Thread adapters
  for graceful teardown (cleanup subscriptions, restore handlers, clear maps)
- WS Client now saves/restores original onmessage (consistent with WS Server)
- WS Client dispatchEvent/addEventListener/removeEventListener are no-ops after close()
- WS Server close() removes all connections and clears local listeners
- Redis close() unsubscribes all channels and removes message listener
- Worker Host/Thread close() restore original onmessage and clear callbacks
- Worker Thread throws clear error if globalThis.postMessage is unavailable
- Add double-call guard to WS Server removeConnection
- Export new adapter interface types (RedisEventTarget, WebSocketClientEventTarget, etc.)
- Add sideEffects: false to package.json for tree-shaking
- Update architecture docs: lifecycle section, close() contract, adapter status updates
- 22 new tests covering close(), handler restoration, idempotency, and context guard

test/event-target-redis.test.ts

@@ -26,6 +26,11 @@ function createMockRedis() {
       }
       return {} as any;
     }),
+    off: vi.fn((event: string, callback: (channel: string, message: string) => void) => {
+      if (event === "message" && messageListener === callback) {
+        messageListener = null;
+      }
+    }),
     publications,
     subscriptions,
     unsubscriptions,
@@ -595,4 +600,102 @@ describe("createRedisEventTarget", () => {
       expect(subscribeClient.unsubscribe).toHaveBeenCalledWith("obj:test2");
     });
   });
+
+  describe("close()", () => {
+    it("unsubscribes from all active channels", () => {
+      const publishClient = createMockRedis();
+      const subscribeClient = createMockRedis();
+      const eventTarget = createRedisEventTarget<TestEvent>({
+        publishClient: publishClient as any,
+        subscribeClient: subscribeClient as any,
+      });
+
+      const listener1 = vi.fn();
+      const listener2 = vi.fn();
+      eventTarget.addEventListener("topic:a", listener1);
+      eventTarget.addEventListener("topic:b", listener2);
+
+      eventTarget.close();
+
+      expect(subscribeClient.unsubscribe).toHaveBeenCalledWith("topic:a");
+      expect(subscribeClient.unsubscribe).toHaveBeenCalledWith("topic:b");
+    });
+
+    it("removes the message listener from subscribeClient", () => {
+      const publishClient = createMockRedis();
+      const subscribeClient = createMockRedis();
+      const eventTarget = createRedisEventTarget<TestEvent>({
+        publishClient: publishClient as any,
+        subscribeClient: subscribeClient as any,
+      });
+
+      eventTarget.close();
+
+      expect(subscribeClient.off).toHaveBeenCalledWith("message", expect.any(Function));
+    });
+
+    it("does not receive messages after close", () => {
+      const publishClient = createMockRedis();
+      const subscribeClient = createMockRedis();
+      const eventTarget = createRedisEventTarget<TestEvent>({
+        publishClient: publishClient as any,
+        subscribeClient: subscribeClient as any,
+      });
+
+      const listener = vi.fn();
+      eventTarget.addEventListener("topic:a", listener);
+
+      eventTarget.close();
+
+      const envelope: EventEnvelope = { type: "topic", id: "a", payload: "hello" };
+      subscribeClient.simulateMessage("topic:a", JSON.stringify(envelope));
+
+      expect(listener).not.toHaveBeenCalled();
+    });
+
+    it("is idempotent", () => {
+      const publishClient = createMockRedis();
+      const subscribeClient = createMockRedis();
+      const eventTarget = createRedisEventTarget<TestEvent>({
+        publishClient: publishClient as any,
+        subscribeClient: subscribeClient as any,
+      });
+
+      const listener = vi.fn();
+      eventTarget.addEventListener("topic:a", listener);
+
+      eventTarget.close();
+      eventTarget.close();
+
+      expect(subscribeClient.unsubscribe).toHaveBeenCalledTimes(1);
+    });
+
+    it("handles close with no subscriptions", () => {
+      const publishClient = createMockRedis();
+      const subscribeClient = createMockRedis();
+      const eventTarget = createRedisEventTarget<TestEvent>({
+        publishClient: publishClient as any,
+        subscribeClient: subscribeClient as any,
+      });
+
+      expect(() => eventTarget.close()).not.toThrow();
+    });
+
+    it("unsubscribes from prefixed channels correctly", () => {
+      const publishClient = createMockRedis();
+      const subscribeClient = createMockRedis();
+      const eventTarget = createRedisEventTarget<TestEvent>({
+        publishClient: publishClient as any,
+        subscribeClient: subscribeClient as any,
+        prefix: "alk:events:",
+      });
+
+      const listener = vi.fn();
+      eventTarget.addEventListener("topic:a", listener);
+
+      eventTarget.close();
+
+      expect(subscribeClient.unsubscribe).toHaveBeenCalledWith("alk:events:topic:a");
+    });
+  });
 });