feature: create event store in preparation of table component

replacement

lib/frontend/stores/eventStore.js

@@ -0,0 +1,35 @@
+import { writable } from 'svelte/store'
+
+import { STORAGE_KEYS } from '../services/storageListener'
+
+const createEventStore = () => {
+  const state = JSON.parse(localStorage.getItem(STORAGE_KEYS.EVENTS) || '[]')
+
+  const { subscribe, set, update } = writable(state)
+
+  const setCalculation = ({ id, link, createdAt, startTime, title }) => {
+    update((prevState) => ([
+      ...prevState,
+      {
+        id,
+        link,
+        createdAt: createdAt.toString(),
+        startTime: startTime.toString(),
+        title,
+      },
+    ]))
+  }
+
+  const getState = () => state
+
+  return {
+    ...state,
+    subscribe,
+    set,
+    update,
+    setCalculation,
+    getState,
+  }
+}
+
+export default createEventStore()