Simplify to transport-only: remove call protocol, add EventEnvelope, expand stream operators

- Remove src/call.ts (PendingRequestMap, CallEventSchema, CallError) — call protocol belongs in @alkdev/operations
- Add EventEnvelope type ({ type, id, payload }) as the cross-platform serialization contract
- Simplify createPubSub: replace PubSubPublishArgsByKey tuple model with PubSubEventMap; publish(type, id, payload) and subscribe(type, id) use explicit id for topic scoping
- Update Redis adapter to serialize/deserialize full EventEnvelope
- Expand operators: add take, reduce, toArray, batch, dedupe, window, flat, groupBy, chain, join
- Remove @alkdev/typebox runtime dependency (was only used by call.ts)
- Remove ./call sub-path export from package.json and tsup config
- Update all architecture docs to reflect transport-only scope, add Worker adapter, remove call protocol references
- Remove docs/architecture/call-protocol.md
- Update AGENTS.md with new source layout and transport-only principle

tsup.config.ts

@@ -4,7 +4,6 @@ export default defineConfig({
   entry: [
     'src/index.ts',
     'src/event-target-redis.ts',
-    'src/call.ts',
   ],
   format: ['esm', 'cjs'],
   dts: true,