feat: initial Go/JS/Rust Origin check-in client SDKs

Standalone clients that resolve a machine unique ID (OS machine ID first,
falling back to a generated UUID persisted to disk), detect hostname/IP/
container/orchestrator, and register+re-ping origin.warky.dev's public
service-checkin endpoint on a daily interval. Ported from icy2's internal
origincheckin package but extended to the full check-in contract and made
dependency-light for external reuse.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

js/test/client.test.ts

@@ -0,0 +1,141 @@
+import { createServer, type IncomingMessage, type Server, type ServerResponse } from "node:http";
+import { describe, expect, it } from "vitest";
+import { OriginClient } from "../src/client.js";
+
+function withServer(
+  handler: (req: IncomingMessage, res: ServerResponse) => void,
+): Promise<{ server: Server; url: string }> {
+  return new Promise((resolve) => {
+    const server = createServer(handler);
+    server.listen(0, "127.0.0.1", () => {
+      const address = server.address();
+      const port = typeof address === "object" && address ? address.port : 0;
+      resolve({ server, url: `http://127.0.0.1:${port}` });
+    });
+  });
+}
+
+describe("OriginClient", () => {
+  it("requires serviceKey/type/version/name", () => {
+    expect(() => new OriginClient({ serviceKey: "", type: "", version: "", name: "" })).toThrow();
+  });
+
+  it("sends the expected payload and headers on checkinOnce", async () => {
+    let gotKey = "";
+    let gotBody: Record<string, unknown> = {};
+    const { server, url } = await withServer((req, res) => {
+      gotKey = req.headers["x-origin-service-key"] as string;
+      let raw = "";
+      req.on("data", (chunk) => {
+        raw += chunk;
+      });
+      req.on("end", () => {
+        gotBody = JSON.parse(raw);
+        res.writeHead(200, { "Content-Type": "application/json" });
+        res.end(
+          JSON.stringify({
+            success: true,
+            service_instance_id: 42,
+            unique_install_id: gotBody.unique_install_id,
+            status: "provisioning",
+            pinged_at: "2026-08-01T00:00:00Z",
+          }),
+        );
+      });
+    });
+
+    try {
+      const client = new OriginClient({
+        url,
+        serviceKey: "test-key",
+        type: "icy2",
+        version: "v1.0.0",
+        name: "icy2-test",
+        installId: "test-install-id",
+      });
+
+      const resp = await client.checkinOnce();
+
+      expect(gotKey).toBe("test-key");
+      expect(gotBody.type).toBe("icy2");
+      expect(gotBody.name).toBe("icy2-test");
+      expect(gotBody.unique_install_id).toBe("test-install-id");
+      expect(resp.success).toBe(true);
+      expect(resp.service_instance_id).toBe(42);
+    } finally {
+      server.close();
+    }
+  });
+
+  it("throws on a non-2xx response", async () => {
+    const { server, url } = await withServer((_req, res) => {
+      res.writeHead(500);
+      res.end();
+    });
+
+    try {
+      const client = new OriginClient({
+        url,
+        serviceKey: "test-key",
+        type: "icy2",
+        version: "v1.0.0",
+        name: "icy2-test",
+        installId: "test-install-id",
+      });
+
+      await expect(client.checkinOnce()).rejects.toThrow();
+    } finally {
+      server.close();
+    }
+  });
+
+  it("does not throw for an unreachable server", async () => {
+    const client = new OriginClient({
+      url: "http://127.0.0.1:1",
+      serviceKey: "test-key",
+      type: "icy2",
+      version: "v1.0.0",
+      name: "icy2-test",
+      installId: "test-install-id",
+    });
+
+    await expect(client.checkinOnce()).rejects.toThrow();
+  });
+
+  it("start() checks in immediately and stop() prevents further calls", async () => {
+    let calls = 0;
+    const { server, url } = await withServer((_req, res) => {
+      calls += 1;
+      res.writeHead(200, { "Content-Type": "application/json" });
+      res.end(
+        JSON.stringify({
+          success: true,
+          service_instance_id: 1,
+          unique_install_id: "x",
+          status: "provisioning",
+          pinged_at: "2026-08-01T00:00:00Z",
+        }),
+      );
+    });
+
+    try {
+      const client = new OriginClient({
+        url,
+        serviceKey: "test-key",
+        type: "icy2",
+        version: "v1.0.0",
+        name: "icy2-test",
+        installId: "test-install-id",
+        intervalHours: 24,
+      });
+
+      client.start();
+      await new Promise((resolve) => setTimeout(resolve, 50));
+      client.stop();
+
+      expect(calls).toBe(1);
+    } finally {
+      server.close();
+    }
+  });
+});