feat(server): add SQLite KV store exposed as $kv in script sandbox

Co-authored-by: Nasyarobby Putra <nasyarobby@gmail.com>

packages/server/test/kv-smoke.js

@@ -0,0 +1,52 @@
+import { migrate } from "../db.js";
+import { createKvApi, kvDelete } from "../kv-store.js";
+import { runScriptSource } from "../script-sandbox.js";
+import { log } from "../logger.js";
+
+await migrate();
+
+const ns = "test/kv-smoke";
+await kvDelete(ns, "counter");
+await kvDelete(ns, "cas");
+
+const api = createKvApi(ns);
+
+await api.set("counter", { n: 1 });
+const v1 = await api.get("counter");
+if (v1?.n !== 1) throw new Error(`expected n=1, got ${JSON.stringify(v1)}`);
+
+const casFail = await api.compareAndSet("cas", null, { first: true });
+if (!casFail.ok || casFail.previous !== null) {
+  throw new Error(`first CAS failed: ${JSON.stringify(casFail)}`);
+}
+
+const casFail2 = await api.compareAndSet("cas", null, { second: true });
+if (casFail2.ok) throw new Error("second CAS with null expected should fail");
+
+const casOk = await api.compareAndSet("cas", { first: true }, { second: true });
+if (!casOk.ok) throw new Error("CAS update should succeed");
+
+const listed = await api.list();
+if (!listed.some((item) => item.key === "cas")) {
+  throw new Error(`list missing cas: ${JSON.stringify(listed)}`);
+}
+
+const script = `
+export default async function () {
+  const prev = await $kv.get("script-key");
+  await $kv.set("script-key", { prev, now: Date.now() });
+  return { prev, namespace: $kv.namespace };
+}
+`;
+
+const out = await runScriptSource("kv-smoke.js", script, { data: {} }, {
+  log,
+  workflowName: ns,
+});
+if (out.namespace !== ns) throw new Error(`wrong namespace: ${out.namespace}`);
+
+await kvDelete(ns, "counter");
+await kvDelete(ns, "cas");
+await kvDelete(ns, "script-key");
+
+console.log("kv smoke test passed");