Improve error boundary UI with status-specific error pages (#21)

* Improve error pages with styled, status-aware UI

Replace the bare-bones error boundary with a proper error page that:
- Renders a minimal Brackt header so users can navigate home
- Shows distinct messages and icons for 401, 403, 404, 500+ errors
- Displays a "Sign in from the home page" hint on 401 so logged-out
  users know how to recover
- Hides internal details in production (stack traces dev-only)
- Uses existing dark theme Tailwind classes for visual consistency

https://claude.ai/code/session_011jv8desa5vhSkjZHSjWZiV

* Address code review feedback on error pages

- Move statusIcon out of ErrorBoundary render as a plain module-level
  function to avoid React re-creating a component type on every render
- Collapse 401 action into a single descriptive button label
  ("Go to Home Page to Sign In") instead of a fragmented button + hint
- Fix details/summary border radius collision by using overflow-hidden
  on the container and removing rounded-md from the summary element;
  separate the pre block with a border-t instead

https://claude.ai/code/session_011jv8desa5vhSkjZHSjWZiV

---------

Co-authored-by: Claude <noreply@anthropic.com>

app/root.tsx

@@ -16,6 +16,7 @@ import { ClerkProvider } from "@clerk/react-router";
 import { dark } from "@clerk/themes";
 import { Toaster } from "~/components/ui/sonner";
 import { isUserAdminByClerkId } from "~/models/user";
+import { AlertCircle, FileQuestion, Lock, ShieldOff, ServerCrash } from "lucide-react";
 
 export const middleware: Route.MiddlewareFunction[] = [clerkMiddleware()];
 
@@ -83,30 +84,95 @@ export default function App({ loaderData }: Route.ComponentProps) {
 }
 
 export function ErrorBoundary({ error }: Route.ErrorBoundaryProps) {
-  let message = "Oops!";
-  let details = "An unexpected error occurred.";
+  let status = 500;
+  let title = "Something Went Wrong";
+  let message = "An unexpected error occurred. Please try again later.";
   let stack: string | undefined;
-
+  let showSignInHint = false;
   if (isRouteErrorResponse(error)) {
-    message = error.status === 404 ? "404" : "Error";
-    details =
-      error.status === 404
-        ? "The requested page could not be found."
-        : error.statusText || details;
-  } else if (import.meta.env.DEV && error && error instanceof Error) {
-    details = error.message;
-    stack = error.stack;
+    status = error.status;
+    switch (error.status) {
+      case 401:
+        title = "Sign In Required";
+        message = "You need to be signed in to access this page.";
+        showSignInHint = true;
+        break;
+      case 403:
+        title = "Access Denied";
+        message = "You don't have permission to view this page.";
+        break;
+      case 404:
+        title = "Page Not Found";
+        message = "The page you're looking for doesn't exist or has been moved.";
+        break;
+      default:
+        title = `Error ${error.status}`;
+        message =
+          typeof error.data === "string" && error.data
+            ? error.data
+            : error.statusText || "Something went wrong.";
+    }
+  } else if (error instanceof Error) {
+    title = "Unexpected Error";
+    message = import.meta.env.DEV ? error.message : "An unexpected error occurred. Please try again later.";
+    stack = import.meta.env.DEV ? error.stack : undefined;
   }
 
   return (
-    <main className="pt-16 p-4 container mx-auto">
-      <h1>{message}</h1>
-      <p>{details}</p>
-      {stack && (
-        <pre className="w-full p-4 overflow-x-auto">
-          <code>{stack}</code>
-        </pre>
-      )}
-    </main>
+    <div className="min-h-screen bg-background text-foreground flex flex-col">
+      <header className="border-b border-border/40 bg-background/95 backdrop-blur">
+        <div className="flex h-16 items-center px-4 md:px-6 lg:px-8">
+          <a href="/" className="font-bold text-xl hover:text-primary transition-colors">
+            Brackt
+          </a>
+        </div>
+      </header>
+
+      <main className="flex-1 flex items-center justify-center p-6">
+        <div className="max-w-md w-full text-center space-y-6">
+          <div className="text-8xl font-bold text-muted-foreground/40 select-none">
+            {status}
+          </div>
+
+          <div className="flex justify-center">
+            {statusIcon(status)}
+          </div>
+
+          <div className="space-y-2">
+            <h1 className="text-2xl font-semibold tracking-tight">{title}</h1>
+            <p className="text-muted-foreground">{message}</p>
+          </div>
+
+          <div className="flex justify-center pt-2">
+            <a
+              href="/"
+              className="inline-flex items-center justify-center rounded-md text-sm font-medium bg-primary text-primary-foreground hover:bg-primary/90 h-9 px-4 py-2 transition-colors"
+            >
+              {showSignInHint ? "Go to Home Page to Sign In" : "Go Home"}
+            </a>
+          </div>
+
+          {stack && (
+            <details className="text-left mt-8 border border-border rounded-md overflow-hidden">
+              <summary className="cursor-pointer text-sm text-muted-foreground px-4 py-3 hover:bg-muted/50">
+                Stack trace (development only)
+              </summary>
+              <pre className="p-4 overflow-x-auto text-xs text-muted-foreground border-t border-border">
+                <code>{stack}</code>
+              </pre>
+            </details>
+          )}
+        </div>
+      </main>
+    </div>
   );
 }
+
+function statusIcon(status: number) {
+  const cls = "h-14 w-14 text-muted-foreground";
+  if (status === 401) return <Lock className={cls} />;
+  if (status === 403) return <ShieldOff className={cls} />;
+  if (status === 404) return <FileQuestion className={cls} />;
+  if (status >= 500) return <ServerCrash className={cls} />;
+  return <AlertCircle className={cls} />;
+}