feat(dashboard): 新增分区 Error Boundary + Suspense 骨架屏（P2）

新增 components/dashboard-section.tsx，包含：

- DashboardSectionErrorBoundary：分区级 Error Boundary，单区块崩溃仅替换该区块不波及整页

- DashboardSectionSkeleton：5 种骨架变体（stats/card/chart/table/list），匹配不同数据区块布局

- DashboardSection：组合 Error Boundary + Suspense + 骨架屏的包装器

将 admin/teacher/student 三个仪表盘视图的每个独立数据区块用 DashboardSection 包裹，i18n 补充 sectionLoadFailed/sectionLoadFailedDesc 翻译键，同步更新架构图 004/005 文档

docs/architecture/005_architecture_data.json

@@ -5822,6 +5822,29 @@
             "purpose": "根据当前小时返回问候语时段 key"
           }
         ],
+        "components": [
+          {
+            "name": "DashboardSection",
+            "path": "components/dashboard-section.tsx",
+            "purpose": "分区 Error Boundary + Suspense + 骨架屏包装器，包裹每个独立数据区块",
+            "variants": ["stats", "card", "chart", "table", "list"],
+            "usedBy": [
+              "admin-dashboard.tsx",
+              "teacher-dashboard-view.tsx",
+              "student-dashboard-view.tsx"
+            ]
+          },
+          {
+            "name": "DashboardSectionErrorBoundary",
+            "path": "components/dashboard-section.tsx",
+            "purpose": "仪表盘分区级 Error Boundary（class component），单区块崩溃仅替换该区块"
+          },
+          {
+            "name": "DashboardSectionSkeleton",
+            "path": "components/dashboard-section.tsx",
+            "purpose": "分区骨架屏，5 种变体匹配不同数据区块布局"
+          }
+        ],
         "dataAccess": [
           {
             "name": "getAdminDashboardData",
@@ -9830,9 +9853,9 @@
               "requirePermission",
               "data-access.getAttendanceRecords"
             ],
-            "usedBy": [
-              "teacher/attendance/page.tsx",
-              "admin/attendance/page.tsx"
+            "usedBy": [],
+            "issues": [
+              "P0: 无调用方——admin/teacher 页面绕过 Action 直接调用 data-access.getAttendanceRecords，违反三层架构"
             ]
           },
           {
@@ -9844,9 +9867,9 @@
               "requirePermission",
               "data-access-stats.getStudentAttendanceSummary"
             ],
-            "usedBy": [
-              "student/attendance/page.tsx",
-              "parent/attendance/page.tsx"
+            "usedBy": [],
+            "issues": [
+              "P0: 无调用方——student/parent 页面绕过 Action 直接调用 data-access-stats.getStudentAttendanceSummary"
             ]
           },
           {
@@ -9858,8 +9881,9 @@
               "requirePermission",
               "data-access-stats.getClassAttendanceStats"
             ],
-            "usedBy": [
-              "teacher/attendance/stats/page.tsx"
+            "usedBy": [],
+            "issues": [
+              "P0: 无调用方——teacher/attendance/stats 页面绕过 Action 直接调用 data-access-stats.getClassAttendanceStats"
             ]
           },
           {
@@ -9994,6 +10018,9 @@
             ],
             "usedBy": [
               "attendance-sheet.tsx"
+            ],
+            "issues": [
+              "P0: 跨模块直查 classEnrollments 表，违反模块间只能通过对方 data-access 通信的规则（应改为调用 classes data-access）"
             ]
           },
           {
@@ -10061,6 +10088,9 @@
             ],
             "usedBy": [
               "admin/attendance/page.tsx"
+            ],
+            "issues": [
+              "P0: 统计失真——调用 getAttendanceRecords（默认 pageSize=20）后对 items 聚合，仅基于前 20 条记录计算总览数据，班级/状态/日期筛选后仍只统计前 20 条"
             ]
           }
         ],
@@ -11643,9 +11673,9 @@
               "requirePermission(ELECTIVE_READ)",
               "data-access.getElectiveCourses (scope, currentUserId)"
             ],
-            "usedBy": [
-              "admin/elective/page.tsx",
-              "teacher/elective/page.tsx"
+            "usedBy": [],
+            "issues": [
+              "P0: 无调用方——admin/teacher 页面绕过 Action 直接调用 data-access.getElectiveCourses，违反三层架构"
             ]
           },
           {
@@ -11658,8 +11688,9 @@
               "requirePermission(ELECTIVE_READ)",
               "data-access-selections.getStudentSelections"
             ],
-            "usedBy": [
-              "待扩展"
+            "usedBy": [],
+            "issues": [
+              "P0: 无调用方——页面绕过 Action 直接调用 data-access-selections.getStudentSelections"
             ]
           },
           {
@@ -11672,8 +11703,9 @@
               "requirePermission(ELECTIVE_SELECT)",
               "data-access-selections.getAvailableCoursesForStudent"
             ],
-            "usedBy": [
-              "待扩展"
+            "usedBy": [],
+            "issues": [
+              "P0: 无调用方——student/elective 页面绕过 Action 直接调用 data-access-selections.getAvailableCoursesForStudent"
             ]
           }
         ],
@@ -12763,8 +12795,8 @@
           }
         ],
         "messages": [
-          "src/shared/i18n/messages/zh-CN/{common,auth,onboarding,classes,errors}.json",
-          "src/shared/i18n/messages/en/{common,auth,onboarding,classes,errors}.json"
+          "src/shared/i18n/messages/zh-CN/{common,auth,onboarding,classes,errors,dashboard,examHomework,announcements,messages}.json",
+          "src/shared/i18n/messages/en/{common,auth,onboarding,classes,errors,dashboard,examHomework,announcements,messages}.json"
         ]
       },
       "routes": {},
@@ -13214,7 +13246,8 @@
         ],
         "attendance": [
           "data-access-stats.getStudentAttendanceSummary",
-          "components.student-attendance-view"
+          "components.student-attendance-view",
+          "types.StudentAttendanceSummary (⚠️ 跨模块 UI 类型依赖：parent-attendance-warning.tsx / parent-attendance-rate-card.tsx / parent-attendance-calendar.tsx 直接 import)"
         ]
       }
     },