rewrite: toast stacking with daisyui toast container

- module-level reactive toast list in composables/toast (setToast signature unchanged, 13 call sites untouched)
- multiple toasts stack simultaneously in daisyUI toast container, each auto-dismisses (3s) with close button
- TransitionGroup enter/leave animation (transform/opacity, honors reduced-motion)
- drop provide/inject queue that blocked consecutive toasts

REFACTOR_PLAN.md

@@ -284,3 +284,11 @@ src/
 - 背景：daisyUI dark 主题的 primary 为紫色，普通主按钮（btn-primary）在深色模式下显示为紫底。
 - 方案：`main.css` 覆写 `.btn-primary` 的 daisyUI 颜色变量（`--btn-color` / `--btn-fg`）——浅色主题黑底白字（#171717/#fff，hover 纯黑）、深色主题白底黑字（#fff/#171717，hover 浅灰）。仅影响 btn-primary；success/error/warning/outline/ghost 等特殊按钮与链接、开关、焦点环均保持原样。
 - 验证：`pnpm build` 通过；浏览器实测深色（白底黑字 New Token）与浅色（黑底白字 Log In）两种主题，特殊按钮未受影响；已恢复维护者的 auto 主题偏好与 admin 会话。
+
+### 增量 7 — Toast 重写：多实例堆叠（维护者反馈）✅
+
+- 背景：原实现为串行队列（processQueue 一次展示一条），连续操作时提示互相阻塞。
+- daisyUI 的 `toast` 组件本身只负责定位与堆叠（容器内多个 `alert` 自动纵向排列），队列/自动消失/动画需应用层实现——已按此重写：
+  - `composables/toast.ts`：模块级响应式 `toasts` 列表，`setToast(message, type?, duration?)` 推入带唯一 id 的条目并定时自动移除（默认 3s）；`useToast()` 签名不变，13 个调用视图零改动；移除原 provide/inject 方案。
+  - `Toast.vue`：daisyUI `toast toast-top toast-end` 容器 + `TransitionGroup` 进出场动画（仅 transform/opacity，配合全局 reduced-motion 降级）、每条带关闭按钮（aria-label）、容器 `aria-live="polite"`。
+- 验证：`pnpm build` 通过；浏览器实测连续触发两条 toast 同时堆叠展示、3s 后全部自动消失。

frontend/src/App.vue

@@ -1,25 +1,8 @@
 <template>
-
   <RouterView />
-  <Toast :queue="toastQueue" />
-
+  <Toast />
 </template>
 
 <script setup lang="ts">
-import { onMounted, ref, provide } from 'vue';
 import Toast from '@/components/common/Toast.vue';
-import { ToastKey } from './composables/toast';
-import type { ToastMessage, ToastType } from './composables/toast';
-
-const toastQueue = ref<ToastMessage[]>([]);
-
-const setToast = (message: string, type: ToastType = 'info', duration?: number) => {
-  toastQueue.value.push({ message, type, duration });
-};
-
-onMounted(() => {
-  // authStore.checkLoginStatus();
-});
-
-provide(ToastKey, { setToast });
 </script>

frontend/src/components/common/Toast.vue

@@ -1,56 +1,50 @@
-<!-- src/components/common/Toast.vue -->
+<!-- src/components/common/Toast.vue：daisyUI toast 容器堆叠展示全部活动提示 -->
 <template>
-  <div aria-live="polite" class="toast toast-top toast-end z-50 mt-16">
-    <div
-      v-if="show && currentMessage"
-      class="alert shadow-lg"
-      :class="{
-        'alert-error': currentMessage.type === 'error',
-        'alert-success': currentMessage.type === 'success',
-        'alert-info': currentMessage.type !== 'error' && currentMessage.type !== 'success',
-      }"
-    >
-      <span>{{ currentMessage.message }}</span>
-    </div>
+  <div aria-live="polite" class="toast toast-top toast-end z-50 mt-16 gap-2">
+    <TransitionGroup name="toast">
+      <div
+        v-for="t in toasts"
+        :key="t.id"
+        role="status"
+        class="alert shadow-lg"
+        :class="{
+          'alert-error': t.type === 'error',
+          'alert-success': t.type === 'success',
+          'alert-info': t.type === 'info',
+        }"
+      >
+        <span class="min-w-0 flex-1 break-words">{{ t.message }}</span>
+        <button type="button" class="btn btn-ghost btn-xs" aria-label="关闭提示" @click="dismiss(t.id)">✕</button>
+      </div>
+    </TransitionGroup>
   </div>
 </template>
 
 <script setup lang="ts">
-import { ref, onUnmounted, watch } from 'vue';
-import type { ToastMessage } from '@/composables/toast';
+import { useToasts } from '@/composables/toast';
 
-const props = defineProps<{
-  queue: ToastMessage[];
-}>();
-
-const show = ref(false);
-const currentMessage = ref<ToastMessage | null>(null);
-let timer: ReturnType<typeof setTimeout> | null = null;
-
-const processQueue = () => {
-  if (props.queue.length === 0) {
-    show.value = false;
-    currentMessage.value = null;
-    return;
-  }
-
-  currentMessage.value = props.queue.shift() ?? null;
-  show.value = true;
-
-  timer = setTimeout(() => {
-    processQueue();
-  }, currentMessage.value?.duration || 3000);
-};
-
-watch(() => props.queue, () => {
-  if (!show.value) {
-    processQueue();
-  }
-}, { deep: true });
-
-onUnmounted(() => {
-  if (timer) {
-    clearTimeout(timer);
-  }
-});
+const { toasts, dismiss } = useToasts();
 </script>
+
+<style scoped>
+/* 只动 transform/opacity；系统开启减弱动态效果时由全局样式禁用 */
+.toast-enter-active,
+.toast-leave-active {
+  transition: opacity 0.25s ease, transform 0.25s ease;
+}
+
+.toast-enter-from {
+  opacity: 0;
+  transform: translateY(-8px);
+}
+
+.toast-leave-to {
+  opacity: 0;
+  transform: translateX(16px);
+}
+
+.toast-leave-active {
+  position: absolute;
+  right: 0;
+}
+</style>

frontend/src/composables/toast.ts

@@ -1,24 +1,35 @@
-import { inject } from 'vue'
-import type { InjectionKey } from 'vue'
+import { ref } from 'vue'
 
 export type ToastType = 'info' | 'success' | 'error'
 
-export type ToastMessage = {
-  message: string
-  type?: ToastType
-  duration?: number
+export type ToastItem = {
+    id: number
+    message: string
+    type: ToastType
+    duration: number
 }
 
-export type ToastContext = {
-  setToast: (message: string, type?: ToastType, duration?: number) => void
+// 模块级共享状态：所有活动 toast 堆叠展示，互不阻塞
+const toasts = ref<ToastItem[]>([])
+let seed = 0
+
+function dismiss(id: number) {
+    toasts.value = toasts.value.filter(t => t.id !== id)
 }
 
-export const ToastKey: InjectionKey<ToastContext> = Symbol('toast')
+export function setToast(message: string, type: ToastType = 'info', duration = 3000) {
+    const id = ++seed
+    toasts.value.push({ id, message, type, duration })
+    if (duration > 0) {
+        setTimeout(() => dismiss(id), duration)
+    }
+}
 
-export function useToast(): ToastContext {
-  const ctx = inject(ToastKey)
-  if (!ctx) {
-    throw new Error('ToastContext 未提供：请在 App 根组件 provide(ToastKey, ...)')
-  }
-  return ctx
+export function useToast() {
+    return { setToast }
+}
+
+// 供 Toast 组件渲染使用
+export function useToasts() {
+    return { toasts, dismiss }
 }