añadida validacion de email contra el back

src/lib/hooks/checkEmail.ts

@@ -0,0 +1,16 @@
+import { apiBase } from "@/stores/url";
+import { get } from "svelte/store";
+
+export async function checkEmail(email: string) {
+  try {
+    const req = await fetch(`${get(apiBase)}/api/users/check-email/${email}`, {
+      method: "GET"
+    });
+    if (req.ok){
+      return (await req.json()).available;
+    }
+    return false;
+  } catch {
+    return false;
+  }
+}