新增 全局错误toast提示；

src/components/ToastContext.tsx

@@ -0,0 +1,87 @@
+import React, { createContext, useContext, useReducer, useState, useEffect } from 'react';
+import { Toast } from './Toast';
+
+type ToastType = 'success' | 'error' | 'warning' | 'info';
+
+export interface ToastMessage {
+  id: string;
+  message: string;
+  type: ToastType;
+  duration?: number;
+}
+
+export interface ToastContextType {
+  addToast: (message: string, type: ToastType, duration?: number) => void;
+  removeToast: (id: string) => void;
+}
+
+const ToastContext = createContext<ToastContextType | undefined>(undefined);
+
+type ToastAction = 
+  | { type: 'ADD_TOAST'; payload: ToastMessage }
+  | { type: 'REMOVE_TOAST'; payload: string };
+
+const toastReducer = (state: ToastMessage[], action: ToastAction): ToastMessage[] => {
+  switch (action.type) {
+    case 'ADD_TOAST':
+      return [...state, action.payload];
+    case 'REMOVE_TOAST':
+      return state.filter(toast => toast.id !== action.payload);
+    default:
+      return state;
+  }
+};
+
+export const ToastProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+  const [toasts, dispatch] = useReducer(toastReducer, []);
+
+  const addToast = (message: string, type: ToastType, duration: number = 5000) => {
+    const id = Date.now().toString();
+    dispatch({ type: 'ADD_TOAST', payload: { id, message, type, duration } });
+  };
+
+  const removeToast = (id: string) => {
+    dispatch({ type: 'REMOVE_TOAST', payload: id });
+  };
+
+  // Auto remove toasts after duration
+  useEffect(() => {
+    const timers = toasts.map(toast => {
+      if (toast.duration === 0) return; // 0 means persistent
+      return setTimeout(() => {
+        removeToast(toast.id);
+      }, toast.duration);
+    });
+
+    return () => {
+      timers.forEach(timer => {
+        if (timer) clearTimeout(timer);
+      });
+    };
+  }, [toasts]);
+
+  return (
+    <ToastContext.Provider value={{ addToast, removeToast }}>
+      {children}
+      <div className="fixed top-4 right-4 z-50 space-y-2">
+        {toasts.map(toast => (
+          <Toast
+            key={toast.id}
+            id={toast.id}
+            message={toast.message}
+            type={toast.type}
+            onClose={removeToast}
+          />
+        ))}
+      </div>
+    </ToastContext.Provider>
+  );
+};
+
+export const useToast = () => {
+  const context = useContext(ToastContext);
+  if (!context) {
+    throw new Error('useToast must be used within a ToastProvider');
+  }
+  return context;
+};