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

docs/architecture/event-targets/worker.md

@@ -1,6 +1,6 @@
 ---
 status: draft
-last_updated: 2026-05-07
+last_updated: 2026-05-08
 ---
 
 # Worker Event Target
@@ -14,15 +14,17 @@ Enables `createPubSub` to work across Worker boundaries. Two factory functions:
 ## API
 
 ```ts
-// Main thread — wraps a Worker instance
-function createWorkerEventTarget<TEvent extends TypedEvent>(
+// Main thread side — wraps a Worker instance
+function createWorkerHostEventTarget<TEvent extends TypedEvent>(
   worker: Worker,
 ): TypedEventTarget<TEvent>;
 
-// Worker thread — wraps parent message port
-function createMainThreadEventTarget<TEvent extends TypedEvent>(): TypedEventTarget<TEvent>;
+// Worker thread side — wraps parent message port
+function createWorkerThreadEventTarget<TEvent extends TypedEvent>(): TypedEventTarget<TEvent>;
 ```
 
+The naming convention: `Host` is the side that owns the `Worker` object (typically the main thread). `Thread` is the side that runs inside the worker (accessing `self.onmessage` / `parentPort`).
+
 ## Protocol
 
 Worker messages use the `EventEnvelope` format over `postMessage`:
@@ -31,9 +33,10 @@ Worker messages use the `EventEnvelope` format over `postMessage`:
 { "type": "call.responded", "id": "uuid-123", "payload": { "output": 42 } }
 ```
 
-### Main Thread → Worker
+### Host → Worker Thread
 
 ```ts
+// Host side (createWorkerHostEventTarget)
 dispatchEvent(event) {
   this.worker.postMessage(event.detail);
   // event.detail is the EventEnvelope
@@ -41,19 +44,20 @@ dispatchEvent(event) {
 }
 ```
 
-### Worker → Main Thread
+### Worker Thread → Host
 
 ```ts
+// Worker thread side (createWorkerThreadEventTarget)
 dispatchEvent(event) {
   globalThis.postMessage(event.detail);
   return true;
 }
 ```
 
-### Receiving
+### Receiving on Host Side
 
 ```ts
-// Main thread side
+// Host side (createWorkerHostEventTarget)
 this.worker.onmessage = (msg) => {
   const envelope = msg.data;
   const topic = `${envelope.type}:${envelope.id}`;
@@ -61,7 +65,10 @@ this.worker.onmessage = (msg) => {
   // dispatch to listeners
 };
 
-// Worker thread side
+### Receiving on Worker Thread Side
+
+```ts
+// Worker thread side (createWorkerThreadEventTarget)
 globalThis.onmessage = (msg) => {
   const envelope = msg.data;
   const topic = `${envelope.type}:${envelope.id}`;