Implement editing of the schedule

Cobbled together minimum viable system for editing the schedule in a way
that propogates updates to connected clients.

app/api/events/route.ts

@@ -1,36 +1,4 @@
-import { Schedule } from "@/app/schedule/types";
-
-function sendMessage(
-	stream: WritableStream<string>,
-	message: string,
-) {
-	const writer = stream.getWriter();
-	writer.ready
-		.then(() => writer.write(message))
-		.catch(console.error)
-		.finally(() => writer.releaseLock())
-	;
-}
-
-let streams = new Set<WritableStream<string>>();
-let lastBroadcastData: string | null = null;
-let lastBroadcastId = 0;
-export function broadcastUpdate(schedule: Schedule) {
-	const id = Date.now();
-	const data = JSON.stringify(schedule);
-	lastBroadcastId = id;
-	lastBroadcastData = data;
-	const message = `id: ${id}\nevent: update\ndata: ${data}\n\n`
-	for (const stream of streams) {
-		sendMessage(stream, message);
-	}
-}
-
-setInterval(() => {
-	for (const stream of streams) {
-		sendMessage(stream, "data: keepalive\n\n");
-	}
-}, 10e3)
+import { addStream, deleteStream } from "./streams";
 
 export async function GET(request: Request) {
 	const encoder = new TextEncoder();
@@ -42,21 +10,15 @@ export async function GET(request: Request) {
 		},
 		flush(controller) {
 			console.log(`finished event stream for ${source}`);
-			streams.delete(stream.writable);
+			deleteStream(stream.writable);
 		},
 		// @ts-expect-error experimental API
 		cancel(reason) {
 			console.log(`cancelled event stream for ${source}`);
-			streams.delete(stream.writable);
+			deleteStream(stream.writable);
 		}
 	})
-	streams.add(stream.writable);
-	if (lastBroadcastId) {
-		sendMessage(
-			stream.writable,
-			`id: ${lastBroadcastData}\nevent: update\ndata: ${lastBroadcastData}\n\n`
-		);
-	}
+	addStream(stream.writable);
 	return new Response(
 		stream.readable,
 		{