refactor: restructure pinia stores, fix calendar, add utilities

- Restructure Pinia store organization from src/stores/ to src/store/ with modular stores
- Update main.ts to use locally created Pinia instance instead of imported pre-configured one
- Fix template syntax errors in Calendar component: correct missing class spacing and incorrect closing tags
- Remove unused calendar demo/example files and documentation
- Add new constant files, token management utilities, and client configuration constants
- Add custom hooks useGoHome and useGoLogin for navigation and login logic

src/store/modules/picture.ts

@@ -0,0 +1,17 @@
+import { defineStore } from "pinia";
+
+export const usePictureStore = defineStore("picture", {
+  state() {
+    return {
+      previewImageData: [], // 预览图片数据
+    };
+  },
+
+  actions: {
+    setPreviewImageData(data) {
+      this.previewImageData = data;
+    },
+  },
+
+  unistorage: true,
+});