feat: add Redis-backed SSE updates

app/sse/[topic]/route.ts

@@ -0,0 +1,34 @@
+import { getServerSession } from "next-auth";
+import { authOptions } from "@/app/api/auth/[...nextauth]/route";
+import {
+  getAdminDiscordIds,
+  getSessionDiscordId,
+} from "@/lib/auth";
+import { isSseTopic, sse } from "@/lib/sse";
+
+export async function GET(
+  request: Request,
+  { params }: { params: Promise<{ topic: string }> },
+) {
+  const { topic } = await params;
+
+  if (!isSseTopic(topic)) {
+    return new Response("Invalid SSE topic", { status: 404 });
+  }
+
+  const endpoint = sse[topic];
+  if (endpoint.adminOnly) {
+    const session = await getServerSession(authOptions);
+    const discordId = getSessionDiscordId(session);
+    if (!discordId || !getAdminDiscordIds().includes(discordId)) {
+      return new Response("Unauthorized", { status: 401 });
+    }
+  }
+
+  try {
+    return await endpoint.stream({ signal: request.signal });
+  } catch (error) {
+    console.error(`Failed to open SSE topic ${topic}`, error);
+    return new Response("SSE unavailable", { status: 503 });
+  }
+}