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/redis.md

@@ -1,6 +1,6 @@
 ---
 status: draft
-last_updated: 2026-05-07
+last_updated: 2026-05-08
 ---
 
 # Redis Event Target
@@ -45,6 +45,7 @@ Currently uses the topic string directly as the Redis channel name (e.g., `call.
 - **No error handling** — connection failures, reconnection, and message parse errors are not handled
 - **No channel prefix** — raw event types as channel names risk collision in shared Redis instances
 - **No unsubscribe cleanup on client disconnect** — if the subscribe client disconnects, registered callbacks remain in the map but will never fire
+- **In-flight messages after unsubscribe** — if `removeEventListener` triggers an `unsubscribe` while a Redis message is in flight, the message may arrive after the callback is removed. This is harmless (the callback set is empty, so the message is a no-op) but worth noting for implementers
 
 ## Test Coverage