feat(worker): CRC32 archive fingerprint compare

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

worker/src/archive/fingerprint.test.ts

@@ -1,7 +1,35 @@
 import { describe, it, expect } from "vitest";
+import { crcFingerprint, fingerprintsMatch } from "./fingerprint.js";
+import type { FileEntry } from "./zip-reader.js";
 
-describe("harness", () => {
-  it("runs", () => {
-    expect(1 + 1).toBe(2);
+const fe = (crc: string | null): FileEntry => ({
+  path: "a", fileName: "a", extension: null,
+  compressedSize: 0n, uncompressedSize: 0n, crc32: crc,
+});
+
+describe("crcFingerprint", () => {
+  it("sorts crcs and marks complete", () => {
+    expect(crcFingerprint([fe("00ff"), fe("00aa")])).toEqual({ crcs: ["00aa", "00ff"], complete: true });
+  });
+  it("is incomplete when any crc is null", () => {
+    expect(crcFingerprint([fe("00aa"), fe(null)]).complete).toBe(false);
+  });
+  it("is incomplete when empty", () => {
+    expect(crcFingerprint([]).complete).toBe(false);
+  });
+});
+
+describe("fingerprintsMatch", () => {
+  it("matches identical crc multisets regardless of order", () => {
+    expect(fingerprintsMatch([fe("01"), fe("02")], [fe("02"), fe("01")])).toBe(true);
+  });
+  it("rejects different counts", () => {
+    expect(fingerprintsMatch([fe("01")], [fe("01"), fe("02")])).toBe(false);
+  });
+  it("rejects disjoint sets", () => {
+    expect(fingerprintsMatch([fe("01")], [fe("09")])).toBe(false);
+  });
+  it("rejects when either side is incomplete", () => {
+    expect(fingerprintsMatch([fe("01"), fe(null)], [fe("01"), fe("02")])).toBe(false);
   });
 });