Fix critical publish() bug, address review findings

CRITICAL: createPubSub.publish() was dispatching CustomEvent with
just the event type (e.g. 'call.responded') instead of the composite
topic string ('call.responded:uuid-123'). This broke all adapters
that rely on topic-scoped dispatch — Redis subscribe/publish
channels didn't match, and WS server fan-out routing would fail.
Fixed to dispatch with the full type:id composite.

Other fixes:
- Add __ prefix runtime guard in publish() (reserved for control)
- Add Redis barrel re-export to src/index.ts (ADR-002 compliance)
- Clarify WS server: adapter's onclose calls removeConnection
  internally; user doesn't need to
- WS client: document null callback no-op, removeEventListener
  edge cases (unregistered callback, null callback)
- WS server: document dispatchEvent always returns true
- Redis spec: document in-flight message edge case after unsubscribe
- Worker adapter: rename createMainThreadEventTarget to
  createWorkerThreadEventTarget, createWorkerEventTarget to
  createWorkerHostEventTarget (fix inverted naming)
- api-surface.md: add PubSub.publish() section documenting the
  type:id composite and __ guard

src/create_pubsub.ts

@@ -69,8 +69,14 @@ export function createPubSub<TEventMap extends PubSubEventMap>(
       id: string,
       payload: TEventMap[TType],
     ) {
+      if (type.startsWith("__")) {
+        throw new Error(
+          `Event types starting with "__" are reserved for adapter control messages. Received: "${type}"`,
+        );
+      }
       const envelope: EventEnvelope<TType, TEventMap[TType]> = { type, id, payload };
-      const event = new CustomEvent(type, { detail: envelope }) as PubSubEvent<
+      const topic = `${type}:${id}`;
+      const event = new CustomEvent(topic, { detail: envelope }) as PubSubEvent<
         TEventMap,
         TType
       >;

src/index.ts

@@ -1,4 +1,5 @@
 export { createPubSub, type PubSub, type PubSubConfig, type PubSubEvent, type PubSubEventTarget, type PubSubEventMap } from "./create_pubsub.js";
 export { type EventEnvelope, type TypedEvent, type TypedEventTarget, type TypedEventListener, type TypedEventListenerObject, type TypedEventListenerOrEventListenerObject } from "./types.js";
 export { filter, map, pipe, take, reduce, toArray, batch, dedupe, window, flat, groupBy, chain, join } from "./operators.js";
-export { Repeater, RepeaterOverflowError, type Push, type Stop, type RepeaterExecutor, type RepeaterBuffer } from "./repeater.js";
+export { Repeater, RepeaterOverflowError, type Push, type Stop, type RepeaterExecutor, type RepeaterBuffer } from "./repeater.js";
+export { createRedisEventTarget, type CreateRedisEventTargetArgs } from "./event-target-redis.js";