Plain operations: last write wins, hash-keyed events, simpler composite

- KV: one write primitive, write(changes) with { key, value? }; writeIfAbsent removed.
  The server executes exactly what clients send and never reads values, so they can be
  encrypted end to end. Adds setFields/getFields on the base class.
- HTTP: no server history or event ids; SSE relays every change (own writes included) and
  the client emits resync when a dropped stream reconnects.
- Composite: writes apply locally, then go to the source (undone locally if refused);
  pushed changes are applied and announced only where they differ from local values;
  offline writes go to a queue store (any KV storage); sync() = replay, diff, replay.
  Removes KVReplicaSet, KVOutbox, KeyCounter, SerialQueue and RetryTimer.
- Events: id = <time>_<sha256(time + canonical data)>, so concurrent appends never
  collide and retries can't duplicate; no versions or ConcurrencyError.
- Event-sourced documents: read, resolve, append, apply; catchUp folds in foreign events;
  getAt takes an event id.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017Qxbkp4tA7G5SCWjzWuxmE

src/index.ts

@@ -4,8 +4,6 @@ export * from './kv-storage/kv-storage-http.js'
 export * from './kv-storage/kv-storage-http-server.js'
 export * from './kv-storage/kv-storage-indexeddb.js'
 export * from './kv-storage/kv-storage-composite.js'
-export * from './kv-storage/kv-replica-set.js'
-export * from './kv-storage/kv-outbox.js'
 export * from './event-storage/base-event-storage.js'
 export * from './event-storage/event-storage-kv.js'
 export * from './document-storage/base-document-storage.js'
@@ -19,10 +17,7 @@ export * from './utils/errors.js'
 export * from './utils/event-emitter.js'
 export * from './utils/extended-json.js'
 export * from './utils/hex.js'
-export * from './utils/key-counter.js'
 export * from './utils/key-range.js'
-export * from './utils/retry-timer.js'
-export * from './utils/serial-queue.js'
 export * from './utils/request-auth.js'
 export * from './utils/json.js'
 export * from './utils/keys.js'