feat: correctly use error boundaries per-page

app/components/page-error.tsx

@@ -0,0 +1,43 @@
+import { RefreshCw, ServerOff } from "lucide-react";
+import { isRouteErrorResponse, useRevalidator } from "react-router";
+
+import { isConnectionError } from "~/server/headscale/api/error-client";
+import cn from "~/utils/cn";
+
+import Button from "./Button";
+import { ErrorBanner } from "./error-banner";
+
+interface PageErrorProps {
+  error: unknown;
+  page: string;
+}
+
+export default function PageError({ error, page }: PageErrorProps) {
+  const { revalidate, state } = useRevalidator();
+
+  if (isRouteErrorResponse(error) && isConnectionError(error.data)) {
+    return (
+      <div className="flex flex-col items-center justify-center py-24 text-center">
+        <ServerOff className={cn("h-12 w-12", "text-mist-400 dark:text-mist-500")} />
+        <h2 className="mt-4 text-lg font-semibold">{page} Unavailable</h2>
+        <p className="mt-1 max-w-sm text-sm text-mist-500 dark:text-mist-400">
+          This page could not be loaded because the Headscale server is unreachable. It will be
+          available once the connection is restored.
+        </p>
+        <Button
+          className="mt-6"
+          variant="light"
+          onPress={() => revalidate()}
+          isDisabled={state === "loading"}
+        >
+          <RefreshCw
+            className={cn("mr-2 inline-block h-4 w-4", state === "loading" && "animate-spin")}
+          />
+          Retry
+        </Button>
+      </div>
+    );
+  }
+
+  return <ErrorBanner className="max-w-2xl" error={error} />;
+}

app/components/status-banner.tsx

@@ -0,0 +1,80 @@
+import { AlertCircle, CloudOff, Info, TriangleAlert, X } from "lucide-react";
+import { useState } from "react";
+
+import cn from "~/utils/cn";
+
+type Variant = "info" | "warning" | "error" | "critical";
+
+interface StatusBannerProps {
+  variant: Variant;
+  title: string;
+  children: React.ReactNode;
+  dismissable?: boolean;
+  className?: string;
+}
+
+const icons: Record<Variant, React.ReactNode> = {
+  info: <Info className="h-5 w-5 shrink-0" />,
+  warning: <TriangleAlert className="h-5 w-5 shrink-0" />,
+  error: <AlertCircle className="h-5 w-5 shrink-0" />,
+  critical: <CloudOff className="h-5 w-5 shrink-0" />,
+};
+
+export default function StatusBanner({
+  variant,
+  title,
+  children,
+  dismissable = true,
+  className,
+}: StatusBannerProps) {
+  const [dismissed, setDismissed] = useState(false);
+
+  if (dismissed) {
+    return null;
+  }
+
+  return (
+    <div
+      role="alert"
+      className={cn(
+        "flex items-start gap-3 rounded-lg border px-4 py-3 text-sm",
+        variant === "info" && [
+          "border-indigo-200 bg-indigo-50 text-indigo-900",
+          "dark:border-indigo-500/30 dark:bg-indigo-500/10 dark:text-indigo-200",
+        ],
+        variant === "warning" && [
+          "border-yellow-300 bg-yellow-50 text-yellow-900",
+          "dark:border-yellow-500/30 dark:bg-yellow-500/10 dark:text-yellow-200",
+        ],
+        variant === "error" && [
+          "border-red-300 bg-red-50 text-red-900",
+          "dark:border-red-500/30 dark:bg-red-500/10 dark:text-red-200",
+        ],
+        variant === "critical" && [
+          "border-red-400 bg-red-100 text-red-900",
+          "dark:border-red-500/40 dark:bg-red-500/20 dark:text-red-100",
+        ],
+        className,
+      )}
+    >
+      {icons[variant]}
+      <div className="flex-1">
+        <p className="font-medium">{title}</p>
+        <div className="mt-0.5 text-current/80">{children}</div>
+      </div>
+      {dismissable && (
+        <button
+          type="button"
+          aria-label="Dismiss"
+          onClick={() => setDismissed(true)}
+          className={cn(
+            "shrink-0 rounded p-0.5 transition-colors",
+            "hover:bg-black/10 dark:hover:bg-white/10",
+          )}
+        >
+          <X className="h-4 w-4" />
+        </button>
+      )}
+    </div>
+  );
+}