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/008-websocket-server-adapter.md

@@ -0,0 +1,69 @@
+---
+id: websocket-server-adapter
+name: Implement WebSocket server event target adapter
+status: pending
+depends_on: [websocket-client-adapter]
+scope: broad
+risk: medium
+impact: component
+level: implementation
+---
+
+## Description
+
+Implement the `createWebSocketServerEventTarget` adapter as specified in `docs/architecture/event-targets/websocket-server.md`.
+
+This is a fan-out (multi-connection) adapter that manages multiple WebSocket connections for the hub/server side. It must implement topic-based fan-out with subscription tracking using `__subscribe`/`__unsubscribe` control events.
+
+Key requirements from the architecture:
+- Factory returns `WebSocketServerEventTarget` which extends `TypedEventTarget` with `addConnection(ws)` and `removeConnection(ws)`
+- `addConnection` sets up `onmessage` and `onclose` handlers on the WebSocket
+- `removeConnection` cleans up subscription maps and event handlers (but does NOT close the WebSocket)
+- `dispatchEvent` sends to only connections subscribed to the event type (topic-based fan-out)
+- `addEventListener` registers local listeners (aggregate from all spokes)
+- Subscription tracking: `Map<string, Set<WebSocket>>` from topic to subscribed connections
+- Control protocol: `__subscribe`/`__unsubscribe` messages from spokes update subscription map
+- Backpressure: configurable threshold (default 1MB) — disconnect slow consumers
+- `onConnection` and `onDisconnection` callbacks for lifecycle events
+- Framework-agnostic: takes raw `WebSocket` instances, doesn't handle HTTP upgrade
+- `dispatchEvent` always returns `true` (errors handled via side effects)
+
+## Acceptance Criteria
+
+- [ ] `src/event-target-websocket-server.ts` exists
+- [ ] `createWebSocketServerEventTarget(options)` returns `WebSocketServerEventTarget`
+- [ ] `WebSocketServerEventTarget` extends `TypedEventTarget` with `addConnection` and `removeConnection`
+- [ ] `addConnection(ws)` sets up `onmessage` and `onclose` handlers
+- [ ] `removeConnection(ws)` cleans up internal state but does not close the WebSocket
+- [ ] `addConnection` `onclose` handler automatically calls `removeConnection`
+- [ ] `dispatchEvent` sends only to connections subscribed to the event type
+- [ ] `addEventListener` registers local listeners (aggregate events from all spokes)
+- [ ] `__subscribe` control events from spokes add connection to topic's subscriber set
+- [ ] `__unsubscribe` control events from spokes remove connection from topic's subscriber set
+- [ ] Duplicate `__subscribe` is idempotent (Set handles naturally)
+- [ ] Invalid topic format in control events is silently ignored
+- [ ] Malformed JSON from spokes is silently ignored (logged)
+- [ ] Backpressure: before `ws.send()`, check `bufferedAmount` against threshold
+- [ ] Backpressure: exceeding threshold closes connection with code 1013
+- [ ] `onBackpressure` callback called before disconnecting
+- [ ] `onConnection` callback receives spoke event target and raw WebSocket
+- [ ] `onDisconnection` callback receives spoke event target and raw WebSocket
+- [ ] `dispatchEvent` always returns `true`
+- [ ] Send failure (ws.send throws) catches error, removes connection, fires `onDisconnection`
+- [ ] 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/websocket-server.md
+- docs/architecture/decisions/003-subscription-control-protocol.md
+- src/types.ts
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion