feat(core): source record snapshots with stable hash and gzipped versions

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/core/test/sync/snapshot.test.ts

@@ -0,0 +1,31 @@
+import { expect, test } from "bun:test";
+import type { SourceRecord } from "@sttracker/plugin-sdk/types";
+import { decodeVersion, encodeVersion, hashRecord, normalizeRecord } from "../../src/sync/snapshot.ts";
+
+const rec = (raw: unknown, entry: Record<string, unknown>): SourceRecord =>
+  ({ key: "k", kind: "entry", work: { title: "T", mediaType: "book", externalIds: { a: "1", b: "2" } }, entry, raw }) as SourceRecord;
+
+test("hash ignores raw payload and key order", async () => {
+  const a = rec({ x: 1 }, { rating: 1, status: "planned" });
+  const b = rec({ y: 2 }, { status: "planned", rating: 1 });
+  expect(await hashRecord(a)).toBe(await hashRecord(b));
+  expect(await hashRecord(a)).toMatch(/^[0-9a-f]{64}$/);
+});
+
+test("hash covers normalised fields, deleted and mergedIntoKey", async () => {
+  const base = rec({}, { rating: 1 });
+  const h = await hashRecord(base);
+  expect(await hashRecord(rec({}, { rating: 2 }))).not.toBe(h);
+  expect(await hashRecord({ ...base, deleted: true })).not.toBe(h);
+  expect(await hashRecord({ ...base, mergedIntoKey: "z" })).not.toBe(h);
+  expect(await hashRecord({ ...base, deleted: false })).toBe(h);
+});
+
+test("versions round-trip the normalised record and the raw payload", () => {
+  const r = rec({ deep: { list: [1, 2] } }, { rating: 5 });
+  const encoded = encodeVersion(r);
+  expect(typeof encoded).toBe("string");
+  const v = decodeVersion(encoded);
+  expect(v.raw).toEqual({ deep: { list: [1, 2] } });
+  expect(v.normalized).toEqual(normalizeRecord(r));
+});