renderer: add basic pinia sample

src/renderer/store/temp.js

@@ -0,0 +1,15 @@
+import { defineStore } from 'pinia'
+
+export const useTempStore = defineStore('temp', {
+  state: () => ({
+    text: 'Sample Text'
+  }),
+  getters: {
+    getText: (state) => state.text
+  },
+  actions: {
+    setText (text) {
+      this.text = text
+    }
+  }
+})