Decompose architecture into atomic, dependency-ordered tasks

19 tasks covering core testing, Redis hardening, WebSocket client/server
adapters, Worker adapter, and final review gates. Iroh adapters are tracked
as a deferred placeholder blocked on the @alkdev/iroh fork.

Phases: core validation → Redis hardening → review gate → WebSocket
adapters → review gate → Worker adapter → review gate → final validation.

tasks/012-worker-adapter-implementation.md

@@ -0,0 +1,57 @@
+---
+id: worker-adapter-implementation
+name: Implement Worker event target adapter(s)
+status: pending
+depends_on: [worker-adapter-rd, review-websocket-adapters]
+scope: moderate
+risk: medium
+impact: component
+level: implementation
+---
+
+## Description
+
+Implement the Worker event target adapter(s) based on the outcome of `worker-adapter-rd`. The architecture specifies two factory functions:
+
+- `createWorkerHostEventTarget(worker: Worker): TypedEventTarget<TEvent>` — wraps a Worker instance on the main thread side
+- `createWorkerThreadEventTarget(): TypedEventTarget<TEvent>` — wraps parent message port on the worker thread side
+
+The naming convention: `Host` is the side that owns the `Worker` object, `Thread` is the side that runs inside the worker.
+
+Key requirements from architecture:
+- Bidirectional — both sides can publish and subscribe
+- Per-worker — each worker gets its own event target on the main thread
+- Messages use `EventEnvelope` format over `postMessage`
+- Structured clone for serialization (but `EventEnvelope` is JSON-serializable for cross-platform)
+- No native deps — works in any environment with Worker support
+- `createWorkerHostEventTarget` wraps a `Worker` instance
+- `createWorkerThreadEventTarget` wraps `self.onmessage`/`self.postMessage` (Web) or `parentPort` (Node)
+
+The scope depends on `worker-adapter-rd` outcome. At minimum, implement Web Worker support.
+
+## Acceptance Criteria
+
+- [ ] `src/event-target-worker.ts` (or split files) exists
+- [ ] `createWorkerHostEventTarget(worker)` creates event target for main thread side
+- [ ] `createWorkerThreadEventTarget()` creates event target for worker thread side
+- [ ] `dispatchEvent` on host side calls `worker.postMessage(event.detail)`
+- [ ] `dispatchEvent` on thread side calls `globalThis.postMessage(event.detail)` (Web) or `parentPort.postMessage(event.detail)` (Node, if supported)
+- [ ] Receiving on host side: `worker.onmessage` parses envelope, creates `CustomEvent` with `type:id`
+- [ ] Receiving on thread side: `globalThis.onmessage` (or `parentPort.on('message')`) parses envelope, creates `CustomEvent`
+- [ ] Both sides support `addEventListener` and `removeEventListener`
+- [ ] No comments in source code (project convention)
+- [ ] Sub-path export added to `package.json` and `tsup.config.ts`
+- [ ] Barrel re-export added to `src/index.ts`
+
+## References
+
+- docs/architecture/event-targets/worker.md
+- src/types.ts
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion