成绩通知：仅在某门课程成绩正式发布后自动发送，按成绩单学生名单通知，不展示具体分数；发布状态与通知同一次提交。

手动发信：移除“成绩通知”选项，只能发送普通通知，原有角色与范围权限保持不变。
选课通知：管理员关闭一轮选课时，自动向每位参与学生发送一条汇总通知，包含最终选中课程及候补未成功课程；候补失效、轮次关闭和通知生成保持原子性。
关闭选课界面会明确提示发送通知，并显示实际通知人数。

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

@@ -54,6 +54,8 @@ public sealed class DevelopmentSqliteMigrator(
         "20260726_29_personal_calendar_subscription";
     private const string OfficialDocumentsMigration =
         "20260726_30_official_documents";
+    private const string UnifiedMessageCenterMigration =
+        "20260726_31_unified_message_center";
 
     public async Task MigrateAsync(CancellationToken cancellationToken = default)
     {
@@ -391,6 +393,19 @@ public sealed class DevelopmentSqliteMigrator(
             OfficialDocumentsMigration,
             officialDocumentsExist ? [] : OfficialDocumentStatements,
             cancellationToken);
+
+        var messageDispatchesExist = await db.Database
+            .SqlQueryRaw<int>(
+                """
+                SELECT COUNT(*) AS "Value"
+                FROM sqlite_master
+                WHERE type = 'table' AND name = 'MessageDispatches'
+                """)
+            .AnyAsync(value => value > 0, cancellationToken);
+        await ApplyMigrationAsync(
+            UnifiedMessageCenterMigration,
+            messageDispatchesExist ? [] : UnifiedMessageCenterStatements,
+            cancellationToken);
     }
 
     private async Task ApplyMigrationAsync(
@@ -1876,4 +1891,30 @@ public sealed class DevelopmentSqliteMigrator(
         """CREATE INDEX "IX_MakeupExamAutoJobs_MakeupExamPlanId_CreatedAt" ON "MakeupExamAutoJobs" ("MakeupExamPlanId", "CreatedAt");""",
         """CREATE INDEX "IX_MakeupExamAutoJobs_Status_CreatedAt" ON "MakeupExamAutoJobs" ("Status", "CreatedAt");""",
     ];
+
+    private static readonly string[] UnifiedMessageCenterStatements =
+    [
+        """
+        CREATE TABLE "MessageDispatches" (
+            "Id" TEXT NOT NULL CONSTRAINT "PK_MessageDispatches" PRIMARY KEY,
+            "SenderUserId" TEXT NOT NULL,
+            "SenderName" TEXT NOT NULL,
+            "Title" TEXT NOT NULL,
+            "Content" TEXT NOT NULL,
+            "Category" INTEGER NOT NULL,
+            "AudienceType" INTEGER NOT NULL,
+            "AudienceId" TEXT NULL,
+            "AudienceName" TEXT NOT NULL,
+            "RecipientCount" INTEGER NOT NULL,
+            "LinkUrl" TEXT NULL,
+            "CreatedAt" TEXT NOT NULL,
+            "UpdatedAt" TEXT NOT NULL
+        );
+        """,
+        """CREATE INDEX "IX_MessageDispatches_SenderUserId_CreatedAt" ON "MessageDispatches" ("SenderUserId", "CreatedAt");""",
+        """ALTER TABLE "Notifications" ADD COLUMN "Category" INTEGER NOT NULL DEFAULT 1;""",
+        """ALTER TABLE "Notifications" ADD COLUMN "MessageDispatchId" TEXT NULL REFERENCES "MessageDispatches" ("Id") ON DELETE CASCADE;""",
+        """CREATE INDEX "IX_Notifications_MessageDispatchId" ON "Notifications" ("MessageDispatchId");""",
+        """CREATE INDEX "IX_Notifications_UserId_Category_CreatedAt" ON "Notifications" ("UserId", "Category", "CreatedAt");"""
+    ];
 }