Initial release: JMAP Webmail Client

A modern, privacy-focused webmail client built with Next.js and the JMAP protocol.
Designed for Stalwart Mail Server.

Features:
- Full email operations (compose, reply, forward, threading)
- Real-time push notifications
- Dark/light theme support
- Mobile responsive design
- Keyboard shortcuts
- Drag-and-drop organization
- i18n (English/French)
- Security-first (external content blocked, HTML sanitization)

app/[locale]/error.tsx

@@ -0,0 +1,53 @@
+"use client";
+
+import { useEffect } from "react";
+import { useTranslations } from "next-intl";
+import { AlertCircle, RefreshCw, Home } from "lucide-react";
+import { Button } from "@/components/ui/button";
+import { useParams, useRouter } from "next/navigation";
+
+/**
+ * Route-level error boundary for locale pages.
+ * Catches errors in the locale layout and its children.
+ */
+export default function LocaleError({
+  error,
+  reset,
+}: {
+  error: Error & { digest?: string };
+  reset: () => void;
+}) {
+  const t = useTranslations("errors");
+  const params = useParams();
+  const router = useRouter();
+
+  useEffect(() => {
+    console.error("Route error:", error);
+  }, [error]);
+
+  return (
+    <div className="min-h-screen flex items-center justify-center bg-background">
+      <div className="text-center max-w-md px-4">
+        <div className="w-16 h-16 mx-auto mb-6 rounded-full bg-red-100 dark:bg-red-900/20 flex items-center justify-center">
+          <AlertCircle className="w-8 h-8 text-red-600 dark:text-red-400" />
+        </div>
+        <h2 className="text-xl font-semibold text-foreground mb-2">
+          {t("page_error_title")}
+        </h2>
+        <p className="text-muted-foreground mb-6">
+          {t("page_error_description")}
+        </p>
+        <div className="flex gap-3 justify-center">
+          <Button variant="outline" onClick={() => router.push(`/${params.locale}`)}>
+            <Home className="w-4 h-4 mr-2" />
+            {t("go_home")}
+          </Button>
+          <Button onClick={reset}>
+            <RefreshCw className="w-4 h-4 mr-2" />
+            {t("try_again")}
+          </Button>
+        </div>
+      </div>
+    </div>
+  );
+}