updating tasks

apps/web/src/components/RootError.tsx

@@ -0,0 +1,56 @@
+import { Link } from "@tanstack/react-router";
+
+interface RootErrorProps {
+  error: Error;
+  reset: () => void;
+}
+
+export default function RootError({ error, reset }: RootErrorProps) {
+  return (
+    <section className="relative flex flex-col items-center justify-center min-h-screen text-center overflow-hidden px-6">
+      <div className="absolute inset-0 -z-10">
+        <div className="absolute top-0 left-1/2 h-72 w-184 -translate-x-1/2 rounded-full bg-(--color-primary) opacity-[0.10] blur-3xl" />
+        <div className="absolute top-10 left-1/2 h-72 w-184 -translate-x-1/2 rounded-full bg-(--color-accent) opacity-[0.10] blur-3xl" />
+      </div>
+
+      <div className="-rotate-1 mb-4">
+        <span className="inline-flex items-center gap-2 rounded-full bg-(--color-surface) px-4 py-1 text-xs font-semibold tracking-widest uppercase text-(--color-accent) border border-(--color-primary-light)">
+          something went wrong
+        </span>
+      </div>
+
+      <h1 className="text-5xl md:text-6xl font-black tracking-tight text-(--color-text) leading-[1.05]">
+        Unexpected{" "}
+        <span className="inline-block rotate-1 px-3 py-1 bg-(--color-primary) text-white rounded-xl">
+          error
+        </span>
+      </h1>
+
+      <p className="mt-6 text-lg font-medium text-(--color-text-muted) max-w-sm">
+        Something crashed. This has been noted —{" "}
+        <span className="text-(--color-accent) font-bold">it's not you</span>.
+      </p>
+
+      {import.meta.env.DEV && (
+        <pre className="mt-4 max-w-xl w-full text-left text-xs bg-(--color-surface) border border-(--color-primary-light) rounded-2xl p-4 overflow-auto text-(--color-text-muted)">
+          {error.message}
+        </pre>
+      )}
+
+      <div className="mt-8 flex gap-3 flex-wrap justify-center">
+        <button
+          onClick={reset}
+          className="px-7 py-3 rounded-full text-white font-bold text-sm bg-(--color-primary) hover:bg-(--color-primary-dark)"
+        >
+          Try again
+        </button>
+        <Link
+          to="/"
+          className="px-7 py-3 rounded-full font-bold text-sm text-(--color-primary) border-2 border-(--color-primary) hover:bg-(--color-surface)"
+        >
+          Back to home
+        </Link>
+      </div>
+    </section>
+  );
+}

apps/web/src/components/RouteError.tsx

@@ -0,0 +1,49 @@
+interface RouteErrorProps {
+  error: Error;
+  reset: () => void;
+}
+
+export default function RouteError({ error, reset }: RouteErrorProps) {
+  return (
+    <section className="relative flex flex-col items-center justify-center py-24 text-center overflow-hidden">
+      <div className="absolute inset-0 -z-10">
+        <div className="absolute top-0 left-1/2 h-72 w-184 -translate-x-1/2 rounded-full bg-(--color-primary) opacity-[0.10] blur-3xl" />
+        <div className="absolute top-10 left-1/2 h-72 w-184 -translate-x-1/2 rounded-full bg-(--color-accent) opacity-[0.10] blur-3xl" />
+      </div>
+
+      <div className="-rotate-1 mb-4">
+        <span className="inline-flex items-center gap-2 rounded-full bg-(--color-surface) px-4 py-1 text-xs font-semibold tracking-widest uppercase text-(--color-accent) border border-(--color-primary-light)">
+          something went wrong
+        </span>
+      </div>
+
+      <h1 className="text-5xl font-black tracking-tight text-(--color-text) leading-[1.05]">
+        This page{" "}
+        <span className="inline-block rotate-1 px-3 py-1 bg-(--color-primary) text-white rounded-xl">
+          crashed
+        </span>
+      </h1>
+
+      <p className="mt-6 text-lg font-medium text-(--color-text-muted) max-w-sm">
+        Something went wrong loading this page.{" "}
+        <span className="text-(--color-accent) font-bold">Try again</span> or
+        head back home.
+      </p>
+
+      {import.meta.env.DEV && (
+        <pre className="mt-4 max-w-xl w-full text-left text-xs bg-(--color-surface) border border-(--color-primary-light) rounded-2xl p-4 overflow-auto text-(--color-text-muted)">
+          {error.message}
+        </pre>
+      )}
+
+      <div className="mt-8 flex gap-3 flex-wrap justify-center">
+        <button
+          onClick={reset}
+          className="px-7 py-3 rounded-full text-white font-bold text-sm bg-(--color-primary) hover:bg-(--color-primary-dark)"
+        >
+          Try again
+        </button>
+      </div>
+    </section>
+  );
+}

apps/web/src/routes/__root.tsx

@@ -2,6 +2,7 @@ import { createRootRoute, Outlet } from "@tanstack/react-router";
 import { TanStackRouterDevtools } from "@tanstack/react-router-devtools";
 import Navbar from "../components/navbar/NavBar";
 import NotFound from "../components/NotFound";
+import RootError from "../components/RootError";
 
 const RootLayout = () => {
   return (
@@ -18,4 +19,5 @@ const RootLayout = () => {
 export const Route = createRootRoute({
   component: RootLayout,
   notFoundComponent: NotFound,
+  errorComponent: RootError,
 });

apps/web/src/routes/play.tsx

@@ -4,6 +4,7 @@ import type { GameSession, GameRequest, AnswerResult } from "@lila/shared";
 import { QuestionCard } from "../components/game/QuestionCard";
 import { ScoreScreen } from "../components/game/ScoreScreen";
 import { GameSetup } from "../components/game/GameSetup";
+import RouteError from "../components/RouteError";
 import { authClient } from "../lib/auth-client";
 
 type GameStartResponse = { success: true; data: GameSession };
@@ -127,6 +128,7 @@ function Play() {
 
 export const Route = createFileRoute("/play")({
   component: Play,
+  errorComponent: RouteError,
   beforeLoad: async () => {
     const { data: session } = await authClient.getSession();
     if (!session) {

documentation/backlog.md

@@ -8,9 +8,6 @@ Labels: `[feature]` `[infra]` `[security]` `[ux]` `[debt]`
 
 Things that are actively in progress or should be picked up immediately. Mostly operational risk and the remaining phase 7 hardening work.
 
-- **React error boundaries** `[ux]`
-  Catch and display runtime errors gracefully instead of crashing the entire app.
-
 - **Pin dependencies in package.json** `[debt]` `[infra]`
   Unpinned deps in a CI/CD pipeline are a real risk. Pin all versions to exact values to prevent unexpected breakage on build.
 
@@ -111,6 +108,7 @@ Directionally right, timing is unclear. Revisit when the next/now work is done.
 
 Shipped milestones, newest first.
 
+- **04 - 2026 - React error boundaries** - Catch and display runtime errors gracefully instead of crashing the entire app.
 - **04 - 2026 - 404 and redirect handling** - Unknown routes return raw errors. Add a catch-all route on the frontend for client-side 404s.
 - **04 - 2026 - Multiplayer GameService unit tests** - round evaluation, scoring, tie-breaking, timeout handling 
 - **04 - 2026 - Security headers with helmet** - Add helmet middleware to set secure HTTP response headers.