Start setting up Next js with the new app router

frontend/src/stores/twaStore.ts

@@ -0,0 +1,14 @@
+import { create } from 'zustand'
+
+interface TWAStore {
+  /** Is the site running in a trusted web activity? */
+  isTWA: boolean | undefined
+  setIsTWA: (isTWA: boolean | undefined) => void
+}
+
+const useTWAStore = create<TWAStore>()(set => ({
+  isTWA: undefined,
+  setIsTWA: isTWA => set({ isTWA }),
+}))
+
+export default useTWAStore