feat: add toast notification system

src/stores/toast.ts

@@ -0,0 +1,43 @@
+import { defineStore } from 'pinia'
+import { ref } from 'vue'
+
+export interface Toast {
+  id: number
+  message: string
+  type: 'success' | 'error' | 'info'
+  exiting?: boolean
+}
+
+export const useToastStore = defineStore('toast', () => {
+  const toasts = ref<Toast[]>([])
+  let nextId = 0
+
+  function addToast(message: string, type: Toast['type'] = 'info') {
+    const id = nextId++
+    toasts.value.push({ id, message, type })
+
+    // Max 3 visible
+    if (toasts.value.length > 3) {
+      toasts.value.shift()
+    }
+
+    // Auto-dismiss after 3s
+    setTimeout(() => removeToast(id), 3000)
+  }
+
+  function removeToast(id: number) {
+    const toast = toasts.value.find(t => t.id === id)
+    if (toast) {
+      toast.exiting = true
+      setTimeout(() => {
+        toasts.value = toasts.value.filter(t => t.id !== id)
+      }, 150)
+    }
+  }
+
+  function success(message: string) { addToast(message, 'success') }
+  function error(message: string) { addToast(message, 'error') }
+  function info(message: string) { addToast(message, 'info') }
+
+  return { toasts, addToast, removeToast, success, error, info }
+})