Feat: LocalStorage API key persistence

storage.js

@@ -0,0 +1,13 @@
+const KEY = 'vibegif_api_key';
+
+export function getApiKey() {
+  return localStorage.getItem(KEY) || '';
+}
+
+export function setApiKey(k) {
+  localStorage.setItem(KEY, k.trim());
+}
+
+export function hasApiKey() {
+  return !!getApiKey();
+}