init: Elden Ring death counter with multi-client server

Deno HTTP + WebSocket server serving three pages:
- / desktop with YOU DIED overlay and keyboard controls
- /mobile touch-optimized control page
- /obs transparent browser source for OBS

Count persisted to counter.json, synced in real time across all
connected clients. Compiles to a self-contained Windows .exe via
deno compile.

server.ts

@@ -0,0 +1,84 @@
+import { join } from "jsr:@std/path";
+
+const dir = import.meta.dirname!;
+
+let deaths = 0;
+const clients = new Set<WebSocket>();
+
+// Load persisted count
+try {
+  const data = JSON.parse(await Deno.readTextFile("counter.json"));
+  deaths = Number(data.count) || 0;
+} catch {
+  // No file yet — start at 0
+}
+
+function broadcast(payload: string) {
+  for (const ws of clients) {
+    if (ws.readyState === WebSocket.OPEN) ws.send(payload);
+  }
+}
+
+async function persist() {
+  await Deno.writeTextFile("counter.json", JSON.stringify({ count: deaths }));
+}
+
+function handleSocket(ws: WebSocket) {
+  ws.onopen = () => {
+    clients.add(ws);
+    ws.send(JSON.stringify({ count: deaths }));
+  };
+
+  ws.onmessage = async (e) => {
+    try {
+      const msg = JSON.parse(e.data);
+      const before = deaths;
+
+      if (msg.action === "increment") deaths = Math.min(3999, deaths + 1);
+      else if (msg.action === "decrement") deaths = Math.max(0, deaths - 1);
+      else if (msg.action === "reset") deaths = 0;
+      else return;
+
+      if (deaths !== before) await persist();
+      broadcast(JSON.stringify({ count: deaths }));
+    } catch {
+      // Ignore malformed messages
+    }
+  };
+
+  ws.onclose = () => clients.delete(ws);
+  ws.onerror = () => clients.delete(ws);
+}
+
+async function handler(req: Request): Promise<Response> {
+  const url = new URL(req.url);
+
+  if (url.pathname === "/ws") {
+    const upgrade = req.headers.get("upgrade") ?? "";
+    if (upgrade.toLowerCase() !== "websocket") {
+      return new Response("WebSocket upgrade required", { status: 426 });
+    }
+    const { socket, response } = Deno.upgradeWebSocket(req);
+    handleSocket(socket);
+    return response;
+  }
+
+  if (url.pathname === "/mobile") {
+    const html = await Deno.readTextFile(join(dir, "mobile.html"));
+    return new Response(html, { headers: { "content-type": "text/html; charset=utf-8" } });
+  }
+
+  if (url.pathname === "/obs") {
+    const html = await Deno.readTextFile(join(dir, "obs.html"));
+    return new Response(html, { headers: { "content-type": "text/html; charset=utf-8" } });
+  }
+
+  // Default: desktop
+  const html = await Deno.readTextFile(join(dir, "desktop.html"));
+  return new Response(html, { headers: { "content-type": "text/html; charset=utf-8" } });
+}
+
+console.log("Elden Ring Counter running on http://localhost:8080");
+console.log("Mobile: http://<your-local-ip>:8080/mobile");
+console.log("Obs: http://<your-local-ip>:8080/obs");
+Deno.serve({ port: 8080 }, handler);