Added composable useToken

src/web/composables/useToken.ts

@@ -0,0 +1,13 @@
+import { ref, watch } from 'vue'
+
+export function useToken() {
+  const token = ref('')
+
+  token.value = localStorage.getItem('token') || ''
+
+  watch(token, newToken => {
+    localStorage.setItem('token', newToken)
+  })
+
+  return { token }
+}