feat(collaboration): 完善在线文档协作与通知闭环

- 新增协作文件夹、文件、不可变修订、成员、会话、回调回执、编辑申请与分享链接数据模型。

- 补齐新建、导入、复制、下载、回收站、恢复、成员授权、所有权转让及文件级权限接口。

- 接入 ONLYOFFICE 共同编辑、历史版本预览与恢复、修订另存副本、导出下载审计和幂等回调保存。

- 增加编辑权限申请、审批通知、项目提醒聚合、通知 Feed、已读处理及历史待办数据回填。

- 支持公开分享的查看或编辑模式、有效期、密码哈希、失败锁定、短时访问凭证与固定分享地址。

- 增加协作者导出、申请编辑、工作表结构保护和所有权管理策略，并纳入项目接口权限矩阵。

- 新增协作文件库、编辑工作区、公开分享页、下载与另存为对话框，以及导航、路由和权限入口。

- 统一网页端与桌面端通知布局，增加沉浸式工作区和浏览器、Tauri 双端全屏能力。

- 扩展运行时文件下载适配、Tauri 环境识别和原生全屏命令，继续保持业务代码运行时边界。

- 加固 ONLYOFFICE 消息桥的同源下载、签名地址隔离和保存为能力校验，并更新桌面发布检查。

- 增加连续数据库迁移、50MB 上传限制、OnlyOffice 中文文案与开发启动路由校验。

- 补充协作、通知、权限、路由、运行时、布局和 OnlyOffice 相关测试及模块说明文档。

frontend/src/composables/useProjectNotifications.ts

@@ -0,0 +1,116 @@
+import { computed, ref } from "vue";
+import { useRoute, useRouter } from "vue-router";
+import { listGeneralNotifications, markGeneralNotificationRead } from "../api/notifications";
+import { useStudyStore } from "../store/study";
+import type { GeneralNotificationFeed, GeneralNotificationItem } from "../types/notifications";
+
+export const PROJECT_NOTIFICATIONS_CHANGED_EVENT = "ctms:project-notifications-changed";
+const POLL_INTERVAL_MS = 60_000;
+
+export const notifyProjectNotificationsChanged = () => {
+  if (typeof window !== "undefined") window.dispatchEvent(new Event(PROJECT_NOTIFICATIONS_CHANGED_EVENT));
+};
+
+const formatNotificationTime = (value: string) => {
+  const date = new Date(value);
+  if (Number.isNaN(date.getTime())) return "";
+  const elapsed = Date.now() - date.getTime();
+  if (elapsed < 60_000) return "刚刚";
+  if (elapsed < 3_600_000) return `${Math.max(1, Math.floor(elapsed / 60_000))} 分钟前`;
+  if (elapsed < 86_400_000) return `${Math.max(1, Math.floor(elapsed / 3_600_000))} 小时前`;
+  return `${date.getMonth() + 1}-${String(date.getDate()).padStart(2, "0")}`;
+};
+
+const notificationTone = (item: GeneralNotificationItem): "danger" | "warning" | "info" => {
+  if (item.priority === "URGENT") return "danger";
+  if (item.priority === "HIGH") return "warning";
+  return "info";
+};
+
+export const useProjectNotifications = () => {
+  const study = useStudyStore();
+  const route = useRoute();
+  const router = useRouter();
+  const headerRemindersLoading = ref(false);
+  const feed = ref<GeneralNotificationFeed>({ unread_count: 0, items: [] });
+  let requestId = 0;
+  let pollTimer: number | undefined;
+
+  const loadHeaderReminders = async () => {
+    const studyId = study.currentStudy?.id;
+    const currentRequest = ++requestId;
+    if (!studyId || route.path.startsWith("/admin")) {
+      feed.value = { unread_count: 0, items: [] };
+      return;
+    }
+    headerRemindersLoading.value = true;
+    try {
+      const { data } = await listGeneralNotifications(studyId, 10);
+      if (currentRequest === requestId && study.currentStudy?.id === studyId) feed.value = data;
+    } catch {
+      // 短时网络异常时保留当前内存中的提醒，避免角标在轮询失败时闪烁消失。
+    } finally {
+      if (currentRequest === requestId) headerRemindersLoading.value = false;
+    }
+  };
+
+  const headerReminderItems = computed(() => feed.value.items.map((item) => ({
+    key: item.id,
+    command: `notification:${item.id}`,
+    title: item.title,
+    description: item.message,
+    timeLabel: formatNotificationTime(item.created_at),
+    tone: notificationTone(item),
+    isRead: Boolean(item.read_at),
+  })));
+  const headerReminderTotal = computed(() => feed.value.unread_count);
+  const headerReminderBadgeValue = computed(() => headerReminderTotal.value > 99 ? "99+" : headerReminderTotal.value);
+
+  const handleReminderCommand = async (command: string) => {
+    if (!command.startsWith("notification:")) return;
+    const notificationId = command.slice("notification:".length);
+    const item = feed.value.items.find((candidate) => candidate.id === notificationId);
+    const studyId = study.currentStudy?.id;
+    if (!item || !studyId) return;
+    if (!item.read_at) {
+      item.read_at = new Date().toISOString();
+      feed.value.unread_count = Math.max(0, feed.value.unread_count - 1);
+      await markGeneralNotificationRead(studyId, item.id).catch(() => {
+        item.read_at = null;
+        feed.value.unread_count += 1;
+      });
+    }
+    if (item.action_path?.startsWith("/")) await router.push(item.action_path);
+  };
+  const handleReminderVisibilityChange = (visible: boolean) => {
+    if (visible) void loadHeaderReminders();
+  };
+
+  const handleWindowFocus = () => { void loadHeaderReminders(); };
+  const startHeaderNotificationPolling = () => {
+    if (pollTimer !== undefined || typeof window === "undefined") return;
+    pollTimer = window.setInterval(() => { void loadHeaderReminders(); }, POLL_INTERVAL_MS);
+    window.addEventListener("focus", handleWindowFocus);
+    window.addEventListener(PROJECT_NOTIFICATIONS_CHANGED_EVENT, handleWindowFocus);
+  };
+  const stopHeaderNotificationPolling = () => {
+    if (pollTimer !== undefined) window.clearInterval(pollTimer);
+    pollTimer = undefined;
+    if (typeof window !== "undefined") {
+      window.removeEventListener("focus", handleWindowFocus);
+      window.removeEventListener(PROJECT_NOTIFICATIONS_CHANGED_EVENT, handleWindowFocus);
+    }
+  };
+
+  return {
+    headerRemindersLoading,
+    headerReminderItems,
+    headerReminderTotal,
+    headerReminderBadgeValue,
+    loadHeaderReminders,
+    handleReminderCommand,
+    handleReminderVisibilityChange,
+    startHeaderNotificationPolling,
+    stopHeaderNotificationPolling,
+  };
+};