学年学期页面新增“设为当前”“归档”“撤销归档”，当前学期不能归档、删除或直接取消；已归档学期需先撤销才能重新设为当前。[BaseDataController.cs (line 286)](/E:/jiaowu/src/Jiaowu.Api/Controllers/BaseDataController.cs:286)

切换后，其他学期自动变为历史态；已归档学期进一步弱化。所有主要学期选择器统一默认当前，并显示“当前 / 历史 / 已归档”。[academicTerms.ts (line 1)](/E:/jiaowu/web/src/utils/academicTerms.ts:1)
桌面使用分层表格，390px 手机端改为独立学期卡片，操作不会再挤压表格。[BaseDataView.vue (line 211)](/E:/jiaowu/web/src/views/BaseDataView.vue:211)
归档定义为“历史显示状态”，不是成绩冻结：补考成绩仍可录入并回写，已发布成绩仍可走成绩更正审批。
已加入 SQLite 开发迁移、MySQL 正式迁移和切换/归档/撤销测试。[20260726143000_AcademicTermArchiving.cs (line 1)](/E:/jiaowu/src/Jiaowu.Api/Infrastructure/Persistence/Migrations/MySql/20260726143000_AcademicTermArchiving.cs:1)

src/Jiaowu.Api/Infrastructure/Persistence/DevelopmentSqliteMigrator.cs

@@ -46,6 +46,8 @@ public sealed class DevelopmentSqliteMigrator(
         "20260725_24_approval_tables";
     private const string AcademicWarningsMigration =
         "20260725_25_academic_warnings";
+    private const string AcademicTermArchivingMigration =
+        "20260726_27_academic_term_archiving";
 
     public async Task MigrateAsync(CancellationToken cancellationToken = default)
     {
@@ -329,6 +331,19 @@ public sealed class DevelopmentSqliteMigrator(
             MakeupExamAutoJobsMigration,
             makeupAutoJobsExist ? [] : MakeupExamAutoJobStatements,
             cancellationToken);
+
+        var academicTermArchivingExists = await db.Database
+            .SqlQueryRaw<int>(
+                """
+                SELECT COUNT(*) AS "Value"
+                FROM pragma_table_info('AcademicTerms')
+                WHERE name = 'IsArchived'
+                """)
+            .AnyAsync(value => value > 0, cancellationToken);
+        await ApplyMigrationAsync(
+            AcademicTermArchivingMigration,
+            academicTermArchivingExists ? [] : AcademicTermArchivingStatements,
+            cancellationToken);
     }
 
     private async Task ApplyMigrationAsync(
@@ -1688,6 +1703,13 @@ public sealed class DevelopmentSqliteMigrator(
         """ALTER TABLE "WarningRules" ADD COLUMN "LastCheckAt" TEXT NULL;"""
     ];
 
+    private static readonly string[] AcademicTermArchivingStatements =
+    [
+        """ALTER TABLE "AcademicTerms" ADD COLUMN "IsArchived" INTEGER NOT NULL DEFAULT 0;""",
+        """ALTER TABLE "AcademicTerms" ADD COLUMN "ArchivedAt" TEXT NULL;""",
+        """CREATE INDEX IF NOT EXISTS "IX_AcademicTerms_IsArchived" ON "AcademicTerms" ("IsArchived");"""
+    ];
+
     private const string TeachingEvaluationMigration = "TeachingEvaluation";
 
     private static readonly string[] TeachingEvaluationStatements =