refactor: update crypto envelope encryption and add canvas serialization support

frontend/src/store/useKeyStore.ts

@@ -0,0 +1,12 @@
+import { create } from "zustand";
+
+interface KeyState {
+  masterKey: CryptoKey | null;
+  setMasterKey: (key: CryptoKey | null) => void;
+}
+
+// this key will be used to encrypt and decrypt the user's data
+export const useKeyStore = create<KeyState>((set) => ({
+  masterKey: null,
+  setMasterKey: (masterKey) => set({ masterKey }),
+}));