Add non-destructive dev seed on startup

src/app/dashboard/alert-button.tsx

@@ -0,0 +1,42 @@
+"use client";
+
+import { useTransition } from "react";
+import { Loader2, BellRing } from "lucide-react";
+import { toast } from "sonner";
+
+import { Button } from "@/components/ui/button";
+import { triggerAlertAction } from "./actions";
+
+export function AlertButton({
+  assignmentId,
+  parentUserId,
+}: {
+  assignmentId: string;
+  parentUserId: string;
+}) {
+  const [isPending, startTransition] = useTransition();
+
+  const handleAlert = () => {
+    if (!confirm("Bist du sicher? Dies löst den Notdienst-Alarm aus.")) return;
+    
+    startTransition(async () => {
+      const result = await triggerAlertAction(assignmentId, parentUserId);
+      if ("error" in result && result.error) {
+        toast.error(result.error);
+      } else {
+        toast.success("Alarm erfolgreich ausgelöst. E-Mail wurde versendet.");
+      }
+    });
+  };
+
+  return (
+    <Button variant="destructive" onClick={handleAlert} disabled={isPending}>
+      {isPending ? (
+        <Loader2 className="mr-2 h-4 w-4 animate-spin" />
+      ) : (
+        <BellRing className="mr-2 h-4 w-4" />
+      )}
+      Alarm auslösen
+    </Button>
+  );
+}