add demo storage

src/storage/hooks/demo-mode.ts

@@ -0,0 +1,7 @@
+import {device, useStorage} from '#/storage'
+
+export function useDemoMode() {
+  const [demoMode = false, setDemoMode] = useStorage(device, ['demoMode'])
+
+  return [demoMode, setDemoMode] as const
+}

src/storage/schema.ts

@@ -10,6 +10,7 @@ export type Device = {
   }
   trendingBetaEnabled: boolean
   devMode: boolean
+  demoMode: boolean
 }
 
 export type Account = {