Set up project structure, source files, and architecture docs

- Copy core source from alkhub_ts/packages/core/pubsub/ with import path fixups
  (typed_event_target.ts → types.ts, .ts → .js extensions)
- Make PubSubPublishArgsByKey exported (was private type, needed by barrel)
- Add package.json with sub-path exports and optional peer deps (ioredis)
- Add tsup.config.ts with multi-entry + splitting for tree-shaking
- Add tsconfig.json, vitest.config.ts, .gitignore
- Add AGENTS.md with project conventions and adapter checklist
- Add architecture docs following taskgraph/alkhub pattern:
  docs/architecture/README.md, api-surface.md, event-targets.md,
  iroh-transport.md, build-distribution.md
- Add ADRs: 001-graphql-yoga-fork, 002-tree-shake-pattern
- Copy migration research doc to docs/research/migration.md
- Dual-license MIT OR Apache-2.0 (matching taskgraph)

docs/architecture/event-targets.md

@@ -0,0 +1,111 @@
+---
+status: draft
+last_updated: 2026-04-30
+---
+
+# Event Target Adapters
+
+In-process, Redis, and WebSocket event targets. All implement `TypedEventTarget<TEvent>`.
+
+## Interface Contract
+
+Every adapter must implement:
+
+| Method | Behavior |
+|--------|----------|
+| `addEventListener(type, callback)` | Register listener for event type. Callback receives `CustomEvent` with typed `detail`. |
+| `dispatchEvent(event)` | Send/dispatch event. Returns `boolean` (always `true` for non-cancelable events). |
+| `removeEventListener(type, callback)` | Unregister listener. Clean up underlying subscription when no listeners remain for a topic. |
+
+## In-Process (Default)
+
+No adapter needed. `createPubSub` uses `new EventTarget()` by default. This works for single-process deployments where all pubsub participants share the same memory.
+
+No explicit `InProcessEventTarget` class — the web standard `EventTarget` already implements the interface. Could be formalized later if a name makes the API clearer, but `new EventTarget()` is already the standard.
+
+## Redis
+
+**Import**: `@alkdev/pubsub/event-target-redis`
+**Peer dep**: `ioredis@^5.0.0` (optional)
+
+### `createRedisEventTarget`
+
+```ts
+function createRedisEventTarget<TEvent extends TypedEvent>(
+  args: CreateRedisEventTargetArgs,
+): TypedEventTarget<TEvent>;
+```
+
+### `CreateRedisEventTargetArgs`
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `publishClient` | `Redis \| Cluster` | Yes | ioredis client for publishing. Can share a connection. |
+| `subscribeClient` | `Redis \| Cluster` | Yes | ioredis client for subscribing. Must be dedicated — Redis requires subscriber connections to only receive messages. |
+| `serializer` | `{ stringify, parse }` | No | Custom serializer. Defaults to `JSON`. |
+
+### How It Works
+
+- `dispatchEvent` → `publishClient.publish(event.type, serializer.stringify(event.detail))`
+- `addEventListener` → `subscribeClient.subscribe(topic)`, track callbacks per topic
+- `removeEventListener` → remove callback; if no callbacks remain for topic, `subscribeClient.unsubscribe(topic)`
+
+### Channel Naming
+
+Currently uses raw event type as Redis channel name (e.g., `session.status:proj_123`). Architecture recommends `alk:events:{eventType}` prefix but this is not yet implemented. Should be configurable: `createRedisEventTarget({ ..., prefix: "alk:events:" })`.
+
+### Limitations (Current)
+
+- **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
+
+### Test Coverage
+
+5 tests in alkhub (publish path only, mocked ioredis). No tests for subscription-receive path, unsubscribe cleanup, or error handling.
+
+## WebSocket
+
+**Import**: `@alkdev/pubsub/event-target-websocket` (not yet implemented)
+**Peer dep**: none (WebSocket is a web standard)
+
+### Design (Spec from `spoke-runner.md`)
+
+```ts
+class WebSocketEventTarget implements TypedEventTarget<any> {
+  private listeners = new Map<string, Set<(event: CustomEvent) => void>>()
+
+  constructor(private ws: WebSocket) {
+    ws.onmessage = (msg) => {
+      const { type, payload } = JSON.parse(msg.data as string)
+      const event = new CustomEvent(type, { detail: payload })
+      for (const listener of this.listeners.get(type) ?? []) {
+        listener(event)
+      }
+    }
+  }
+
+  dispatchEvent(event: CustomEvent): boolean {
+    this.ws.send(JSON.stringify({ type: event.type, payload: event.detail }))
+    return true
+  }
+
+  addEventListener(type: string, listener: (event: CustomEvent) => void): void { ... }
+  removeEventListener(type: string, listener: (event: CustomEvent) => void): void { ... }
+}
+```
+
+### Key Properties
+
+- **Bidirectional** — `dispatchEvent` sends over WS, `addEventListener` receives from WS
+- **Per-connection** — hub creates one per spoke connection
+- **JSON framing** — WebSocket provides native message boundaries (no length-prefix needed)
+- **No native deps** — works in browsers and Node
+
+### Gap: Reconnection
+
+WebSocket connections drop. On reconnect, the spoke must re-register with the hub (same `hub.register` flow). The `WebSocketEventTarget` itself is per-connection — a new connection means a new event target instance. Reconnection logic belongs to the spoke lifecycle, not the event target.
+
+### Gap: Hub-Side Architecture
+
+The hub needs per-connection event target + `PendingRequestMap` creation on accept, cleanup on disconnect. This is a hub architectural concern, not a pubsub concern. See `@alkdev/alkhub_ts/docs/architecture/spoke-runner.md`.