feat(web): notification bell with polling and dropdown

web/src/components/layout/NotificationBell.vue

@@ -1,7 +1,73 @@
 <template>
-  <span class="text-sm text-gray-400">🔔</span>
+  <NPopover
+    trigger="click"
+    placement="bottom-end"
+    @update:show="onOpen"
+  >
+    <template #trigger>
+      <NBadge
+        :value="store.unreadCount"
+        :max="99"
+        :show="store.unreadCount > 0"
+      >
+        <NButton text>
+          <span class="text-lg">🔔</span>
+        </NButton>
+      </NBadge>
+    </template>
+    <div class="w-80 max-h-96 overflow-auto">
+      <div
+        v-if="store.items.length === 0"
+        class="p-4 text-gray-500 text-sm"
+      >
+        暂无通知
+      </div>
+      <div
+        v-for="n in store.items"
+        :key="n.id"
+        class="p-3 border-b border-gray-100 dark:border-gray-700 last:border-0"
+      >
+        <div class="text-sm font-medium">
+          {{ n.title }}
+        </div>
+        <div class="text-xs text-gray-500 mt-1">
+          {{ n.body }}
+        </div>
+      </div>
+      <div
+        v-if="store.unreadCount > 0"
+        class="p-2 border-t border-gray-100 dark:border-gray-700"
+      >
+        <NButton
+          size="small"
+          text
+          @click="onMarkAll"
+        >
+          全部标记为已读
+        </NButton>
+      </div>
+    </div>
+  </NPopover>
 </template>
 
 <script setup lang="ts">
-// I6 占位：真实未读轮询 + 弹层在 I6 实现。
+import { NPopover, NBadge, NButton } from 'naive-ui'
+import { notificationsApi } from '@/api/notifications'
+import { useNotificationsStore } from '@/stores/notifications'
+import { useUnreadPoller } from '@/composables/useNotifications'
+
+const store = useNotificationsStore()
+useUnreadPoller()
+
+async function onOpen(open: boolean) {
+  if (!open) return
+  const { items } = await notificationsApi.list(false, 50)
+  store.setItems(items)
+}
+
+async function onMarkAll() {
+  await notificationsApi.markAllRead()
+  store.setUnreadCount(0)
+  store.setItems(store.items.map((i) => ({ ...i, read_at: new Date().toISOString() })))
+}
 </script>

web/src/composables/useNotifications.ts

@@ -0,0 +1,31 @@
+import { onMounted, onUnmounted, ref } from 'vue'
+import { notificationsApi } from '@/api/notifications'
+import { useNotificationsStore } from '@/stores/notifications'
+
+const POLL_INTERVAL_MS = 30_000
+
+export function useUnreadPoller() {
+  const store = useNotificationsStore()
+  let timer: ReturnType<typeof setInterval> | null = null
+  const error = ref<string | null>(null)
+
+  async function refresh() {
+    try {
+      const { count } = await notificationsApi.unreadCount()
+      store.setUnreadCount(count)
+    } catch (e) {
+      error.value = String(e)
+    }
+  }
+
+  onMounted(() => {
+    refresh()
+    timer = setInterval(refresh, POLL_INTERVAL_MS)
+  })
+
+  onUnmounted(() => {
+    if (timer) clearInterval(timer)
+  })
+
+  return { refresh, error }
+}