feat(frontend): add ErrorState primitive

src/components/ui/error-state.tsx

@@ -0,0 +1,62 @@
+import { AlertCircle } from "lucide-react";
+import { Button } from "@/components/ui/button";
+import { cn } from "@/lib/utils";
+
+type ErrorStateProps = {
+  /** All-caps instrument label, defaults to "ERROR". */
+  eyebrow?: string;
+  /** One-line plain-language summary of what went wrong. */
+  message: string;
+  /** Optional secondary detail (e.g. error.message or status code). */
+  detail?: string;
+  /** Optional retry handler — renders an outline "Retry" button. */
+  onRetry?: () => void;
+  className?: string;
+};
+
+/**
+ * Error surface state.
+ * Voice: destructive-hairline row with an "ERROR" eyebrow and a one-line
+ * message. No alarm colors — uses the existing --destructive token at low
+ * opacity so the chrome stays the headline.
+ */
+export function ErrorState({
+  eyebrow = "ERROR",
+  message,
+  detail,
+  onRetry,
+  className,
+}: ErrorStateProps) {
+  return (
+    <div
+      className={cn(
+        "surface rounded-xl border border-destructive/30 p-4",
+        "flex items-center gap-3",
+        className,
+      )}
+      role="alert"
+    >
+      <AlertCircle
+        className="h-4 w-4 text-destructive shrink-0"
+        strokeWidth={1.75}
+        aria-hidden
+      />
+      <div className="flex-1 min-w-0">
+        <div className="text-[10.5px] font-semibold uppercase tracking-[0.18em] text-destructive/80">
+          {eyebrow}
+        </div>
+        <div className="text-sm text-foreground/90 truncate">{message}</div>
+        {detail ? (
+          <div className="text-xs text-muted-foreground truncate mt-0.5">
+            {detail}
+          </div>
+        ) : null}
+      </div>
+      {onRetry ? (
+        <Button variant="outline" size="sm" onClick={onRetry}>
+          Retry
+        </Button>
+      ) : null}
+    </div>
+  );
+}