✨ Added toast notification function and optimized related component styles

frontend/src/components/toast/toastStore.ts

@@ -0,0 +1,55 @@
+import { defineStore } from 'pinia';
+import { ref } from 'vue';
+import type { Toast, ToastOptions } from './types';
+
+export const useToastStore = defineStore('toast', () => {
+  const toasts = ref<Toast[]>([]);
+  let idCounter = 0;
+
+  /**
+   * 添加一个 Toast
+   */
+  const add = (options: ToastOptions): string => {
+    const id = `toast-${Date.now()}-${idCounter++}`;
+    
+    const toast: Toast = {
+      id,
+      message: options.message,
+      type: options.type || 'info',
+      title: options.title,
+      duration: options.duration ?? 4000,
+      position: options.position || 'top-right',
+      closable: options.closable ?? true,
+      createdAt: Date.now(),
+    };
+
+    toasts.value.push(toast);
+    
+    return id;
+  };
+
+  /**
+   * 移除指定 Toast
+   */
+  const remove = (id: string) => {
+    const index = toasts.value.findIndex(t => t.id === id);
+    if (index > -1) {
+      toasts.value.splice(index, 1);
+    }
+  };
+
+  /**
+   * 清空所有 Toast
+   */
+  const clear = () => {
+    toasts.value = [];
+  };
+
+  return {
+    toasts,
+    add,
+    remove,
+    clear,
+  };
+});
+