Cron: add scheduler, wakeups, and run history

src/cron/schedule.test.ts

@@ -0,0 +1,26 @@
+import { describe, expect, it } from "vitest";
+
+import { computeNextRunAtMs } from "./schedule.js";
+
+describe("cron schedule", () => {
+  it("computes next run for cron expression with timezone", () => {
+    // Saturday, Dec 13 2025 00:00:00Z
+    const nowMs = Date.parse("2025-12-13T00:00:00.000Z");
+    const next = computeNextRunAtMs(
+      { kind: "cron", expr: "0 9 * * 3", tz: "America/Los_Angeles" },
+      nowMs,
+    );
+    // Next Wednesday at 09:00 PST -> 17:00Z
+    expect(next).toBe(Date.parse("2025-12-17T17:00:00.000Z"));
+  });
+
+  it("computes next run for every schedule", () => {
+    const anchor = Date.parse("2025-12-13T00:00:00.000Z");
+    const now = anchor + 10_000;
+    const next = computeNextRunAtMs(
+      { kind: "every", everyMs: 30_000, anchorMs: anchor },
+      now,
+    );
+    expect(next).toBe(anchor + 30_000);
+  });
+});