fix(push): reject phone input shorter than 10 digits (was accepting '7')

src/components/client/PushSubscriptionBanner.jsx

@@ -16,6 +16,7 @@ const apiHeaders = {
 const normalizePhone = (phone) => {
   if (!phone) return "";
   const clean = String(phone).replace(/\D/g, "");
+  if (clean.length < 10) return ""; // too short to be a real number
   if (clean.startsWith("8")) return "7" + clean.slice(1);
   if (!clean.startsWith("7")) return "7" + clean;
   return clean;