test: set up jest-expo and cover the Zustand store

package.json

@@ -8,7 +8,10 @@
     "android": "expo start --android",
     "ios": "expo start --ios",
     "web": "expo start --web",
-    "lint": "expo lint"
+    "lint": "expo lint",
+    "typecheck": "tsc --noEmit",
+    "test": "jest",
+    "build": "expo export --platform web"
   },
   "dependencies": {
     "@babel/plugin-transform-runtime": "^7.29.0",
@@ -49,9 +52,14 @@
     "zustand": "^5.0.11"
   },
   "devDependencies": {
+    "@testing-library/react-native": "^13.3.3",
+    "@types/jest": "^29.5.14",
     "@types/react": "~19.1.0",
     "eslint": "^9.25.0",
     "eslint-config-expo": "~10.0.0",
+    "jest": "^29.7.0",
+    "jest-expo": "~54.0.0",
+    "react-test-renderer": "^19.1.0",
     "typescript": "~5.9.2"
   },
   "private": true