feat(deploy): notify clients of new releases

app/api/active/route.ts

@@ -0,0 +1,16 @@
+import { connection } from "next/server";
+
+import { normalizeDeploymentId } from "@/lib/deployment/version";
+import { createEventStream, eventStreamHeaders } from "@/lib/events/sse";
+
+export async function GET(request: Request) {
+  await connection();
+  const deploymentId =
+    normalizeDeploymentId(process.env.NEXT_DEPLOYMENT_ID) ?? "development";
+  const channel = createEventStream({ signal: request.signal });
+  channel.sendNamed("deployment", deploymentId);
+
+  return new Response(channel.stream, {
+    headers: eventStreamHeaders(),
+  });
+}