feat: add AI Digital Employee agent orchestrator with pipeline tracking

- New AgentPipeline model with JSONB pipeline_data for stages/leads/summary
- AgentOrchestrator service chains DiscoveryService search→analyze→outreach→auto-save
- 3 new API endpoints: POST /agent/start, GET /agent/pipelines, GET /agent/{id}
- Full Agent dashboard Vue component with stats, pipeline grid, leads table, outreach preview
- Sidebar redesigned with AI Agent as primary entry point
- Updated PROGRESS.md, AGENTS.md, DATABASE_SCHEMA.md with latest state

user-frontend/src/layouts/UserLayout.vue

@@ -16,6 +16,7 @@
         :collapse-transition="false"
         @select="showMobileMenu = false"
       >
+        <el-menu-item index="/agent"><el-icon><MagicStick /></el-icon><span>{{ $t('nav.agent') || 'AI数字员工' }}</span></el-menu-item>
         <el-menu-item index="/discovery"><el-icon><Search /></el-icon><span>{{ $t('nav.discovery') }}</span></el-menu-item>
         <el-menu-item index="/workspace"><el-icon><Odometer /></el-icon><span>{{ $t('nav.workspace') }}</span></el-menu-item>
         <el-menu-item index="/customers"><el-icon><User /></el-icon><span>{{ $t('nav.customers') }}</span></el-menu-item>
@@ -137,13 +138,6 @@ const beianInfo = computed(() => {
   return { icp: '京ICP备2026007249号-1', gongan: '京公网安备11011502039545号', gonganLink: 'https://beian.mps.gov.cn/#/query/webSearch?code=11011502039545', showGongan: true }
 })
 
-onMounted(async () => {
-  try {
-    const res = await getUnreadCount()
-    unread.value = res.count || res || 0
-  } catch { /* ignore */ }
-})
-
 function handleLogout() {
   auth.logout()
   router.push('/')