Ship Steam login, D1 player sync, and cached「我」dashboard.

Players get a fast TTL-backed homepage (local profile / Cloudflare D1) with dense UI polish; login unlocks /home without blocking on every OpenDota refresh.

Co-authored-by: Cursor <cursoragent@cursor.com>

web/frontend/functions/api/auth/logout.js

@@ -0,0 +1,34 @@
+/**
+ * POST|GET /api/auth/logout — clear session cookie.
+ */
+import { jsonResponse, sessionCookieHeaderForRequest } from "./_steam_common.js";
+
+function clear(context) {
+  const origin = new URL(context.request.url).origin;
+  const wantsHtml = (context.request.headers.get("Accept") || "").includes("text/html");
+  if (wantsHtml || context.request.method === "GET") {
+    return new Response(null, {
+      status: 302,
+      headers: {
+        Location: `${origin}/`,
+        "Set-Cookie": sessionCookieHeaderForRequest(context.request, "", { clear: true }),
+        "Cache-Control": "no-store",
+      },
+    });
+  }
+  return jsonResponse(
+    { ok: true },
+    200,
+    {
+      "Set-Cookie": sessionCookieHeaderForRequest(context.request, "", { clear: true }),
+    }
+  );
+}
+
+export async function onRequestGet(context) {
+  return clear(context);
+}
+
+export async function onRequestPost(context) {
+  return clear(context);
+}