feat(dashboard): 仪表盘模块审计重构 — 权限校验 + i18n + 逻辑抽离

基于 dashboard-audit-report.md 审计结论，对仪表盘模块进行 P0/P1 级修复：

- 新增 4 个 dashboard 权限点（DASHBOARD_ADMIN/TEACHER/STUDENT/PARENT_READ），补充到 permissions.ts 和角色-权限映射

- 新建 actions.ts：4 个 Server Action 均调用 requirePermission() 校验权限，消除 admin 页面零鉴权、teacher/student/parent 仅 requireAuth 的安全隐患

- 根重定向页 /dashboard 改用 resolvePermissions() + 权限点判断，不再 role === xxx 硬编码

- 新建 lib/dashboard-utils.ts：抽取 toWeekday / countStudentAssignments / sortUpcomingAssignments / filterTodaySchedule / computeTeacherMetrics / getGreetingKey 纯函数，与 UI 分离，便于单测

- 新建 messages/{zh-CN,en}/dashboard.json 翻译文件，i18n request.ts 加载 dashboard 命名空间；所有视图组件接入 useTranslations / getTranslations，消除中英混杂硬编码

- 重构 4 个角色 page.tsx：通过 actions 获取数据，generateMetadata 使用 i18n

- 同步更新架构图 004 / 005 文档（dashboard exports / permissions / 文件清单）

docs/architecture/005_architecture_data.json

@@ -121,7 +121,11 @@
     "LESSON_PLAN_READ": "lesson_plan:read",
     "LESSON_PLAN_UPDATE": "lesson_plan:update",
     "LESSON_PLAN_DELETE": "lesson_plan:delete",
-    "LESSON_PLAN_PUBLISH": "lesson_plan:publish"
+    "LESSON_PLAN_PUBLISH": "lesson_plan:publish",
+    "DASHBOARD_ADMIN_READ": "dashboard:admin_read",
+    "DASHBOARD_TEACHER_READ": "dashboard:teacher_read",
+    "DASHBOARD_STUDENT_READ": "dashboard:student_read",
+    "DASHBOARD_PARENT_READ": "dashboard:parent_read"
   },
   "rolePermissions": {
     "admin": [
@@ -176,7 +180,8 @@
       "ELECTIVE_MANAGE",
       "ELECTIVE_READ",
       "EXAM_PROCTOR",
-      "EXAM_PROCTOR_READ"
+      "EXAM_PROCTOR_READ",
+      "DASHBOARD_ADMIN_READ"
     ],
     "teacher": [
       "EXAM_CREATE",
@@ -216,7 +221,8 @@
       "ELECTIVE_MANAGE",
       "ELECTIVE_READ",
       "EXAM_PROCTOR",
-      "EXAM_PROCTOR_READ"
+      "EXAM_PROCTOR_READ",
+      "DASHBOARD_TEACHER_READ"
     ],
     "student": [
       "EXAM_READ",
@@ -236,7 +242,8 @@
       "MESSAGE_DELETE",
       "DIAGNOSTIC_READ",
       "ELECTIVE_SELECT",
-      "ELECTIVE_READ"
+      "ELECTIVE_READ",
+      "DASHBOARD_STUDENT_READ"
     ],
     "parent": [
       "EXAM_READ",
@@ -248,7 +255,8 @@
       "ATTENDANCE_READ",
       "MESSAGE_SEND",
       "MESSAGE_READ",
-      "MESSAGE_DELETE"
+      "MESSAGE_DELETE",
+      "DASHBOARD_PARENT_READ"
     ],
     "grade_head": [
       "EXAM_CREATE",
@@ -5724,8 +5732,96 @@
     },
     "dashboard": {
       "path": "src/modules/dashboard",
-      "description": "各角色仪表盘数据聚合与展示",
+      "description": "各角色仪表盘数据聚合与展示（含权限校验 + i18n + 纯逻辑工具函数）",
       "exports": {
+        "actions": [
+          {
+            "name": "getAdminDashboardAction",
+            "signature": "() => Promise<AdminDashboardData>",
+            "deps": [
+              "shared/lib/auth-guard.requirePermission",
+              "dashboard/data-access.getAdminDashboardData",
+              "Permissions.DASHBOARD_ADMIN_READ"
+            ],
+            "usedBy": [
+              "admin/dashboard/page.tsx"
+            ]
+          },
+          {
+            "name": "getTeacherDashboardAction",
+            "signature": "() => Promise<TeacherDashboardData & { metrics: TeacherDashboardMetrics }>",
+            "deps": [
+              "shared/lib/auth-guard.requirePermission",
+              "classes/data-access.getTeacherClasses/getClassSchedule/getTeacherIdForMutations",
+              "homework/data-access.getHomeworkAssignments/getHomeworkSubmissions/getTeacherGradeTrends",
+              "users/data-access.getUserBasicInfo",
+              "dashboard/lib/dashboard-utils.computeTeacherMetrics",
+              "Permissions.DASHBOARD_TEACHER_READ"
+            ],
+            "usedBy": [
+              "teacher/dashboard/page.tsx"
+            ]
+          },
+          {
+            "name": "getStudentDashboardAction",
+            "signature": "() => Promise<{ student, dashboardProps }>",
+            "deps": [
+              "shared/lib/auth-guard.requirePermission",
+              "users/data-access.getCurrentStudentUser",
+              "classes/data-access.getStudentClasses/getStudentSchedule",
+              "homework/data-access.getStudentHomeworkAssignments/getStudentDashboardGrades",
+              "dashboard/lib/dashboard-utils.countStudentAssignments/sortUpcomingAssignments/toWeekday/filterTodaySchedule",
+              "Permissions.DASHBOARD_STUDENT_READ"
+            ],
+            "usedBy": [
+              "student/dashboard/page.tsx"
+            ]
+          },
+          {
+            "name": "getParentDashboardAction",
+            "signature": "() => Promise<{ data, hasChildren }>",
+            "deps": [
+              "shared/lib/auth-guard.requirePermission",
+              "parent/data-access.getParentDashboardData",
+              "Permissions.DASHBOARD_PARENT_READ"
+            ],
+            "usedBy": [
+              "parent/dashboard/page.tsx"
+            ]
+          }
+        ],
+        "lib": [
+          {
+            "name": "toWeekday",
+            "signature": "(d: Date) => Weekday",
+            "purpose": "Date 转 1-7 周几（周一=1，周日=7）"
+          },
+          {
+            "name": "countStudentAssignments",
+            "signature": "(assignments, now, dueSoonWindowDays?) => StudentAssignmentStats",
+            "purpose": "单次遍历统计学生作业：即将到期/已逾期/已批改"
+          },
+          {
+            "name": "sortUpcomingAssignments",
+            "signature": "(assignments, limit?) => StudentHomeworkAssignmentListItem[]",
+            "purpose": "按截止日期升序排序取前 N 条"
+          },
+          {
+            "name": "filterTodaySchedule",
+            "signature": "(schedule, weekday, classNameById?) => StudentTodayScheduleItem[] | TeacherTodayScheduleItem[]",
+            "purpose": "筛选指定周几课表并按开始时间排序"
+          },
+          {
+            "name": "computeTeacherMetrics",
+            "signature": "(classes, schedule, assignments, submissions, gradeTrends, now) => TeacherDashboardMetrics",
+            "purpose": "计算教师仪表盘派生指标：待批改数/进行中作业/平均分/提交率/今日课表/待批改列表"
+          },
+          {
+            "name": "getGreetingKey",
+            "signature": "(now: Date) => 'morning' | 'afternoon' | 'evening'",
+            "purpose": "根据当前小时返回问候语时段 key"
+          }
+        ],
         "dataAccess": [
           {
             "name": "getAdminDashboardData",
@@ -5740,7 +5836,7 @@
               "DataScope"
             ],
             "usedBy": [
-              "admin/dashboard/page.tsx"
+              "dashboard/actions.getAdminDashboardAction"
             ]
           }
         ],