refactor(dashboard): V2 审计重构 — i18n 补齐 + 共享抽象 + 单测 + a11y

V2 审计报告（docs/architecture/audit/dashboard-audit-report-v2.md）发现并修复：

- P0 i18n：10 个子组件硬编码字符串全部接入 next-intl（teacher-quick-actions /
  teacher-classes-card / teacher-homework-card / teacher-schedule /
  recent-submissions / teacher-grade-trends / student-grades-card /
  student-today-schedule-card / student-upcoming-assignments-card /
  admin-dashboard），新增 ~50 个翻译键
- P1 共享抽象：新增 DashboardGreetingHeader 组件，消除 teacher/student
  头部 90% 重复代码，两个 Header 改为薄包装
- P2 单测：为 6 个纯函数添加 31 个单元测试
  （tests/integration/dashboard/dashboard-utils.test.ts）
- P2 a11y：admin 表格 caption、teacher/student 视图语义化标签
  （header / section aria-label / aside aria-label）
- 同步架构图 004/005

docs/architecture/005_architecture_data.json

@@ -6055,6 +6055,11 @@
             "name": "RecentSubmissions",
             "file": "teacher-dashboard/RecentSubmissions",
             "purpose": "最近提交"
+          },
+          {
+            "name": "DashboardGreetingHeader",
+            "file": "dashboard-greeting-header",
+            "purpose": "共享问候头部组件（V2 抽象，消除 teacher/student 头部 90% 重复代码，接收 userName 和可选 actions slot）"
           }
         ]
       }
@@ -8329,6 +8334,80 @@
             ]
           }
         ],
+        "statsService": [
+          {
+            "name": "computeGradeStats",
+            "signature": "(rows: RawScoreRow[]) => GradeStats | null",
+            "file": "stats-service.ts",
+            "purpose": "从原始成绩行计算班级统计（均分、中位数、标准差、及格率、优秀率、最高分、最低分、参考人数）（P1-1 新增：从 data-access.getClassGradeStats 抽取为纯函数）",
+            "usedBy": [
+              "data-access.getClassGradeStats"
+            ]
+          },
+          {
+            "name": "computeAverageScore",
+            "signature": "(scores: number[]) => number",
+            "file": "stats-service.ts",
+            "purpose": "计算分数平均值（空数组返回 0）（P1-1 新增：从 data-access.getStudentGradeSummary 抽取为纯函数）",
+            "usedBy": [
+              "data-access.getStudentGradeSummary"
+            ]
+          },
+          {
+            "name": "buildGradeTrendPoints",
+            "signature": "(rows: RawScoreRow[]) => GradeTrendPoint[]",
+            "file": "stats-service.ts",
+            "purpose": "构建成绩趋势数据点（按考试标题分组，归一化分数 0-100）（P1-1 新增：从 data-access-analytics.getGradeTrend 抽取为纯函数）",
+            "usedBy": [
+              "data-access-analytics.getGradeTrend"
+            ]
+          },
+          {
+            "name": "computeTrendAverage",
+            "signature": "(points: GradeTrendPoint[]) => number",
+            "file": "stats-service.ts",
+            "purpose": "计算趋势数据点的平均分（P1-1 新增：从 data-access-analytics.getGradeTrend 抽取为纯函数）",
+            "usedBy": [
+              "data-access-analytics.getGradeTrend"
+            ]
+          },
+          {
+            "name": "computeClassComparisonStats",
+            "signature": "(rows: RawScoreRow[]) => Pick<ClassComparisonItem, 'averageScore' | 'passRate' | 'excellentRate' | 'studentCount'>",
+            "file": "stats-service.ts",
+            "purpose": "计算班级对比统计（均分、及格率、优秀率、参考人数）（P1-1 新增：从 data-access-analytics.getClassComparison 抽取为纯函数）",
+            "usedBy": [
+              "data-access-analytics.getClassComparison"
+            ]
+          },
+          {
+            "name": "computeSubjectComparisonStats",
+            "signature": "(scores: number[]) => Pick<SubjectComparisonItem, 'averageScore' | 'passRate' | 'excellentRate' | 'maxScore' | 'minScore'>",
+            "file": "stats-service.ts",
+            "purpose": "计算科目对比统计（均分、及格率、优秀率、最高分、最低分）（P1-1 新增：从 data-access-analytics.getSubjectComparison 抽取为纯函数）",
+            "usedBy": [
+              "data-access-analytics.getSubjectComparison"
+            ]
+          },
+          {
+            "name": "computeGradeDistribution",
+            "signature": "(rows: RawScoreRow[]) => GradeDistributionResult",
+            "file": "stats-service.ts",
+            "purpose": "计算分数分布（90-100/80-89/70-79/60-69/<60 五个区间）（P1-1 新增：从 data-access-analytics.getGradeDistribution 抽取为纯函数）",
+            "usedBy": [
+              "data-access-analytics.getGradeDistribution"
+            ]
+          },
+          {
+            "name": "buildRankingTrendPoints",
+            "signature": "(byTitle: Map<string, RankingTrendEntry>, targetStudentId: string) => RankingTrendPoint[]",
+            "file": "stats-service.ts",
+            "purpose": "构建排名趋势数据点（按考试标题排序、计算每次考试学生排名）（P1-1 新增：从 data-access-ranking.getRankingTrend 抽取为纯函数）",
+            "usedBy": [
+              "data-access-ranking.getRankingTrend"
+            ]
+          }
+        ],
         "components": [
           {
             "name": "GradeRecordForm",
@@ -8433,6 +8512,15 @@
             "usedBy": [
               "teacher/grades/stats/page.tsx"
             ]
+          },
+          {
+            "name": "WidgetBoundary",
+            "file": "components/widget-boundary.tsx",
+            "purpose": "通用 Widget 边界组件（Error Boundary + Suspense + Skeleton 组合，含 a11y 属性 role=alert/aria-live/aria-label）（P1-5 新增）",
+            "deps": [
+              "shared/components/ui/skeleton",
+              "shared/components/ui/button"
+            ]
           }
         ]
       }
@@ -9109,19 +9197,20 @@
     },
     "messaging": {
       "path": "src/modules/messaging",
-      "description": "站内消息系统：用户间私信收发（支持回复链）、站内通知（多态类型：message/announcement/homework/grade），SiteHeader 通知下拉菜单展示未读数",
+      "description": "站内私信系统：用户间私信收发（支持回复链）。通知相关 UI 组件和 CRUD Action 已迁移至 notifications 模块（P1-4 修复）",
       "exports": {
         "actions": [
           {
             "name": "sendMessageAction",
             "permission": "MESSAGE_SEND",
             "signature": "(prevState: ActionState<string> | null, formData: FormData) => Promise<ActionState<string>>",
-            "purpose": "发送消息（同时通过 notifications dispatcher 为收件人创建多渠道通知；支持 parentMessageId 回复）",
+            "purpose": "发送消息（同时通过 notifications dispatcher 为收件人创建多渠道通知；支持 parentMessageId 回复；P2-11 新增 trackEvent 埋点）",
             "deps": [
               "requirePermission",
               "shared/db",
               "data-access.createMessage",
               "notifications.dispatcher.sendNotification",
+              "trackEvent",
               "revalidatePath"
             ],
             "usedBy": [
@@ -9132,11 +9221,12 @@
             "name": "markMessageAsReadAction",
             "permission": "MESSAGE_READ",
             "signature": "(id: string) => Promise<ActionState<void>>",
-            "purpose": "标记消息已读（设置 readAt）",
+            "purpose": "标记消息已读（设置 readAt；P2-11 新增 trackEvent 埋点）",
             "deps": [
               "requirePermission",
               "schema.MessageIdSchema",
               "data-access.markMessageAsRead",
+              "trackEvent",
               "revalidatePath"
             ],
             "usedBy": [
@@ -9148,11 +9238,12 @@
             "name": "deleteMessageAction",
             "permission": "MESSAGE_DELETE",
             "signature": "(id: string) => Promise<ActionState<void>>",
-            "purpose": "删除消息（仅发送者或接收者可删）",
+            "purpose": "删除消息（仅发送者或接收者可删；P2-11 新增 trackEvent 埋点）",
             "deps": [
               "requirePermission",
               "schema.MessageIdSchema",
               "data-access.deleteMessage",
+              "trackEvent",
               "revalidatePath"
             ],
             "usedBy": [
@@ -9162,14 +9253,14 @@
           {
             "name": "getMessagesAction",
             "permission": "MESSAGE_READ",
-            "signature": "(params?: { type?, page?, pageSize? }) => Promise<ActionState<PaginatedResult<MessageListItem>>>",
-            "purpose": "获取消息列表（收件箱/已发送，分页）",
+            "signature": "(params?: { type?, page?, pageSize?, keyword? }) => Promise<ActionState<PaginatedResult<MessageListItem>>>",
+            "purpose": "获取消息列表（收件箱/已发送，分页，关键词搜索；客户端通过 useMessageSearch hook 调用）",
             "deps": [
               "requirePermission",
               "data-access.getMessages"
             ],
             "usedBy": [
-              "message-list.tsx"
+              "message-list.tsx (via useMessageSearch hook)"
             ]
           },
           {
@@ -9201,47 +9292,16 @@
             ]
           },
           {
-            "name": "getNotificationsAction",
+            "name": "getUnreadMessageCountAction",
             "permission": "MESSAGE_READ",
-            "signature": "(params?: { page?, pageSize? }) => Promise<ActionState<PaginatedResult<NotificationListItem>>>",
-            "purpose": "获取当前用户通知列表（分页）",
+            "signature": "() => Promise<ActionState<number>>",
+            "purpose": "获取当前用户未读私信计数（unread-message-badge 组件每 60 秒轮询）",
             "deps": [
               "requirePermission",
-              "data-access.getNotifications"
+              "data-access.getUnreadMessageCount"
             ],
             "usedBy": [
-              "notification-dropdown.tsx",
-              "notification-list.tsx"
-            ]
-          },
-          {
-            "name": "markNotificationAsReadAction",
-            "permission": "MESSAGE_READ",
-            "signature": "(id: string) => Promise<ActionState<void>>",
-            "purpose": "标记单条通知已读",
-            "deps": [
-              "requirePermission",
-              "data-access.markNotificationAsRead",
-              "revalidatePath"
-            ],
-            "usedBy": [
-              "notification-dropdown.tsx",
-              "notification-list.tsx"
-            ]
-          },
-          {
-            "name": "markAllNotificationsAsReadAction",
-            "permission": "MESSAGE_READ",
-            "signature": "() => Promise<ActionState<void>>",
-            "purpose": "标记所有通知已读",
-            "deps": [
-              "requirePermission",
-              "data-access.markAllNotificationsAsRead",
-              "revalidatePath"
-            ],
-            "usedBy": [
-              "notification-dropdown.tsx",
-              "notification-list.tsx"
+              "unread-message-badge.tsx"
             ]
           },
           {
@@ -9251,7 +9311,7 @@
             "purpose": "获取当前用户的通知偏好设置（首次访问自动创建默认记录）",
             "deps": [
               "requirePermission",
-              "notification-preferences.getNotificationPreferences"
+              "notifications.preferences.getNotificationPreferences"
             ],
             "usedBy": [
               "settings/page.tsx",
@@ -9266,7 +9326,7 @@
             "deps": [
               "requirePermission",
               "schema.UpdateNotificationPreferencesSchema",
-              "notification-preferences.upsertNotificationPreferences",
+              "notifications.preferences.upsertNotificationPreferences",
               "revalidatePath"
             ],
             "usedBy": [
@@ -9362,70 +9422,23 @@
               "shared.db.schema.messages"
             ],
             "usedBy": [
-              "待扩展"
+              "getUnreadMessageCountAction",
+              "unread-message-badge.tsx"
             ]
           },
           {
-            "name": "getNotifications",
-            "signature": "(userId: string, params?: { page?, pageSize? }) => Promise<PaginatedResult<NotificationListItem>>",
+            "name": "getMessagesPageData",
+            "signature": "(userId: string) => Promise<{ messages: PaginatedResult<Message>, notifications: PaginatedResult<Notification> }>",
             "file": "data-access.ts",
-            "purpose": "re-export shim（实际逻辑在 notifications/data-access.ts，P0-4 / P1-5 修复后迁移）",
+            "purpose": "P1-5 新增：消息首页编排函数，一次性获取消息列表和通知列表（通知通过动态 import notifications/data-access）",
             "deps": [
+              "data-access.getMessages",
               "notifications.data-access.getNotifications"
             ],
             "usedBy": [
-              "getNotificationsAction",
               "messages/page.tsx"
             ]
           },
-          {
-            "name": "createNotification",
-            "signature": "(input: CreateNotificationInput) => Promise<string>",
-            "file": "data-access.ts",
-            "purpose": "re-export shim（实际逻辑在 notifications/data-access.ts，P0-4 / P1-5 修复后迁移）",
-            "deps": [
-              "notifications.data-access.createNotification"
-            ],
-            "usedBy": [
-              "notifications.dispatcher (via in-app-channel)"
-            ]
-          },
-          {
-            "name": "markNotificationAsRead",
-            "signature": "(id: string, userId: string) => Promise<void>",
-            "file": "data-access.ts",
-            "purpose": "re-export shim（实际逻辑在 notifications/data-access.ts，P0-4 / P1-5 修复后迁移）",
-            "deps": [
-              "notifications.data-access.markNotificationAsRead"
-            ],
-            "usedBy": [
-              "markNotificationAsReadAction"
-            ]
-          },
-          {
-            "name": "markAllNotificationsAsRead",
-            "signature": "(userId: string) => Promise<void>",
-            "file": "data-access.ts",
-            "purpose": "re-export shim（实际逻辑在 notifications/data-access.ts，P0-4 / P1-5 修复后迁移）",
-            "deps": [
-              "notifications.data-access.markAllNotificationsAsRead"
-            ],
-            "usedBy": [
-              "markAllNotificationsAsReadAction"
-            ]
-          },
-          {
-            "name": "getUnreadNotificationCount",
-            "signature": "(userId: string) => Promise<number>",
-            "file": "data-access.ts",
-            "purpose": "re-export shim（实际逻辑在 notifications/data-access.ts，P0-4 / P1-5 修复后迁移）",
-            "deps": [
-              "notifications.data-access.getUnreadNotificationCount"
-            ],
-            "usedBy": [
-              "待扩展"
-            ]
-          },
           {
             "name": "getRecipients",
             "signature": "(ctx: AuthContext) => Promise<RecipientOption[]>",
@@ -9629,21 +9642,26 @@
             "purpose": "写消息表单（收件人 Select、主题 Input、内容 Textarea，支持回复模式）"
           },
           {
-            "name": "NotificationDropdown",
-            "file": "components/notification-dropdown.tsx",
-            "purpose": "SiteHeader 通知下拉菜单（Bell 图标 + 未读数 Badge，滚动列表，标记已读，查看全部链接）"
-          },
+            "name": "UnreadMessageBadge",
+            "file": "components/unread-message-badge.tsx",
+            "purpose": "未读消息计数徽章（侧边栏 Messages 导航项旁显示，每 60 秒轮询 getUnreadMessageCountAction）"
+          }
+        ],
+        "hooks": [
           {
-            "name": "NotificationList",
-            "file": "components/notification-list.tsx",
-            "purpose": "通知完整列表（全部标记已读、单条标记已读、查看链接）"
+            "name": "useMessageSearch",
+            "file": "hooks/use-message-search.ts",
+            "purpose": "P1-7 新增：消息搜索 hook（400ms 防抖 + 请求竞态取消，通过 requestIdRef 匹配最新请求）",
+            "usedBy": [
+              "message-list.tsx"
+            ]
           }
         ]
       }
     },
     "notifications": {
       "path": "src/modules/notifications",
-      "description": "通知渠道集成层：基于用户通知偏好（notification_preferences）将通知分发到站内消息/SMS/微信公众号/邮件多渠道。所有渠道实现统一 NotificationChannelSender 接口，dispatcher 按偏好并行发送。支持 Mock 模式（开发环境无需外部服务）。",
+      "description": "通知渠道集成层：基于用户通知偏好（notification_preferences）将通知分发到站内消息/SMS/微信公众号/邮件多渠道。所有渠道实现统一 NotificationChannelSender 接口，dispatcher 按偏好并行发送。支持 Mock 模式（开发环境无需外部服务）。P1-4 修复后新增通知 UI 组件和通知 CRUD Server Action。",
       "exports": {
         "actions": [
           {
@@ -9673,6 +9691,66 @@
             "usedBy": [
               "待扩展"
             ]
+          },
+          {
+            "name": "getNotificationsAction",
+            "permission": "MESSAGE_READ",
+            "signature": "(params?: { page?, pageSize?, unreadOnly? }) => Promise<ActionState<PaginatedResult<Notification>>>",
+            "purpose": "P1-4 新增（从 messaging 迁移）：获取当前用户通知列表（分页）",
+            "deps": [
+              "requirePermission",
+              "data-access.getNotifications"
+            ],
+            "usedBy": [
+              "notification-dropdown.tsx",
+              "notification-list.tsx"
+            ]
+          },
+          {
+            "name": "getUnreadNotificationCountAction",
+            "permission": "MESSAGE_READ",
+            "signature": "() => Promise<ActionState<number>>",
+            "purpose": "P1-4 新增（从 messaging 迁移）：获取当前用户未读通知计数",
+            "deps": [
+              "requirePermission",
+              "data-access.getUnreadNotificationCount"
+            ],
+            "usedBy": [
+              "notification-dropdown.tsx"
+            ]
+          },
+          {
+            "name": "markNotificationAsReadAction",
+            "permission": "MESSAGE_READ",
+            "signature": "(notificationId: string) => Promise<ActionState<string>>",
+            "purpose": "P1-4 新增（从 messaging 迁移）：标记单条通知已读；P2-11 新增 trackEvent 埋点",
+            "deps": [
+              "requirePermission",
+              "schema.NotificationIdSchema",
+              "data-access.markNotificationAsRead",
+              "trackEvent",
+              "revalidatePath"
+            ],
+            "usedBy": [
+              "notification-dropdown.tsx",
+              "notification-list.tsx"
+            ]
+          },
+          {
+            "name": "markAllNotificationsAsReadAction",
+            "permission": "MESSAGE_READ",
+            "signature": "() => Promise<ActionState<string>>",
+            "purpose": "P1-4 新增（从 messaging 迁移）：标记所有通知已读；P2-11 新增 trackEvent 埋点",
+            "deps": [
+              "requirePermission",
+              "data-access.markAllNotificationsAsRead",
+              "trackEvent",
+              "revalidatePath"
+            ],
+            "usedBy": [
+              "notification-dropdown.tsx",
+              "notification-list.tsx"
+            ]
           }
         ],
         "dispatcher": [
@@ -10029,6 +10107,18 @@
               "messaging (via re-export)"
             ]
           }
+        ],
+        "components": [
+          {
+            "name": "NotificationList",
+            "file": "components/notification-list.tsx",
+            "purpose": "P1-4 新增（从 messaging 迁移）：通知完整列表（全部标记已读、单条标记已读、查看链接）"
+          },
+          {
+            "name": "NotificationDropdown",
+            "file": "components/notification-dropdown.tsx",
+            "purpose": "P1-4 新增（从 messaging 迁移）：SiteHeader 通知下拉菜单（Bell 图标 + 未读数 Badge，每 30 秒轮询，滚动列表，标记已读，查看全部链接）"
+          }
         ]
       }
     },
@@ -12517,6 +12607,8 @@
         "lib/node-summary.ts",
         "lib/rf-mappers.ts",
         "config/block-registry.tsx",
+        "providers/lesson-plan-provider.tsx",
+        "services/default-data-service.ts",
         "data-access.ts",
         "data-access-versions.ts",
         "data-access-templates.ts",
@@ -12549,7 +12641,29 @@
         "components/blocks/text-study-block.tsx",
         "components/blocks/exercise-block.tsx",
         "components/blocks/reflection-block.tsx"
-      ]
+      ],
+      "i18n": {
+        "namespace": "lessonPreparation",
+        "status": "implemented",
+        "messageFiles": [
+          "shared/i18n/messages/zh-CN/lesson-preparation.json",
+          "shared/i18n/messages/en/lesson-preparation.json"
+        ]
+      },
+      "auditFixes": {
+        "P0-1": "publish-service.ts 跨模块直查修复：改用 exams/classes data-access",
+        "P0-2": "i18n 接入：17 个组件改造为 useTranslations/getTranslations",
+        "P0-3": "buildScopeCondition 按 scope 类型精确过滤（class_taught/grade_managed/class_members/children）",
+        "P1-1": "as never 断言替换为类型守卫函数；BLOCK_TYPE_LABELS/LESSON_PLAN_STATUS_LABELS 改为 i18n 键",
+        "P1-2": "新增 LessonPlanErrorBoundary 错误边界",
+        "P1-3": "新增 4 个 Skeleton 骨架屏组件",
+        "P1-4": "alert/confirm/window.location.reload 替换为 toast/AlertDialog/router.refresh",
+        "P1-5": "新增 LessonPlanProvider + Context 注入数据服务，支持多实例",
+        "P1-7": "新增 4 个角色配置（TEACHER/ADMIN/STUDENT/PARENT）+ ROLE_CONFIGS 注册表",
+        "P1-8": "新增 BLOCK_REGISTRY 注册表，node-edit-panel 配置驱动渲染",
+        "P2-1": "5 个组件添加 role=dialog/aria-modal/aria-label",
+        "P2-4": "预留 LessonPlanTracker 接口 + noopTracker 默认实现"
+      }
     }
   },
   "dbTables": {