功能(提醒)：统一项目提醒中心与桌面通知链路

增加通用提醒状态、数据库迁移和定时同步，覆盖风险时效、文件回执、项目里程碑、访视窗口与协作申请。

新增网页端和桌面端提醒中心、真实投递诊断与固定隐私通知正文，并补齐登录来源聚合、测试和说明文档。

frontend/src/router/index.ts

@@ -31,6 +31,7 @@ const EmailSettings = () => import("../views/admin/EmailSettings.vue");
 const ProjectDetail = () => import("../views/admin/ProjectDetail.vue");
 const ProjectOverview = () => import("../views/ia/ProjectOverview.vue");
 const ProjectMilestones = () => import("../views/ia/ProjectMilestones.vue");
+const ProjectNotifications = () => import("../views/ProjectNotifications.vue");
 const FeeContracts = () => import("../views/fees/ContractFees.vue");
 const FeeContractDetail = () => import("../views/fees/ContractFeeDetail.vue");
 const DrugShipments = () => import("../views/ia/DrugShipments.vue");
@@ -149,6 +150,12 @@ const routes: RouteRecordRaw[] = [
         component: ProjectMilestones,
         meta: { title: TEXT.menu.projectMilestones, requiresStudy: true },
       },
+      {
+        path: "project/notifications",
+        name: "ProjectNotifications",
+        component: ProjectNotifications,
+        meta: { title: "提醒中心", requiresStudy: true },
+      },
       {
         path: "fees/contracts",
         name: "FeeContracts",