Shared, platform-neutral Sync Protocol 1.0 contracts and deterministic client state machine for WebObsidian Central Sync. It includes strict Zod schemas/types, path policy, SHA-256 helpers, replay/conflict primitives, golden fixtures, and ordered manifest/catch-up/apply-intent/offline-queue orchestration.

import { OrderedSyncClient, HandshakeResponseSchema, PROTOCOL_VERSION } from '@picassio/sync-core';

Adapters provide persistence, transport, and local materialization; this package performs no filesystem, Obsidian, browser, or credential storage itself. A client must durably record an apply intent before local materialization and advance/acknowledge its cursor only afterward. Wake and polling work flush durable local operations before pulling remote events. Adapters that maintain a separate dirty-path marker can call enqueue(), durably clear that marker, and then call flush() so the server echo cannot race the local preparation boundary. Servers advertising ordered-batch-stop-v1 allow ordered publication in protocol-sized batches; older servers remain at one operation/request. Optional lifecycle observers expose safe bootstrap/progress boundaries only after the corresponding persistence transition.