已完善个人教学日历订阅。

主要能力：
教师、学生可在“我的课表”启用订阅、复制 URL、唤起日历客户端或下载一次性 ICS。
自动覆盖固定课程、调停课后的最新安排、考试/监考、补考，以及灵活课程提醒。
采用独立随机订阅标识和 HMAC 签名；重置或停用后旧地址立即失效。
支持 ETag 条件请求和一小时刷新提示，减少日历客户端重复同步。
订阅地址按实际前端 API 地址生成，兼容独立部署域名。
已增加窄屏弹窗最大宽度和纵向操作布局。

src/Jiaowu.Api/Infrastructure/Persistence/Migrations/MySql/20260726190000_PersonalCalendarSubscription.cs

@@ -0,0 +1,40 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Jiaowu.Api.Infrastructure.Persistence.Migrations.MySql
+{
+    /// <inheritdoc />
+    public partial class PersonalCalendarSubscription : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<DateTime>(
+                name: "CalendarSubscriptionCreatedAt",
+                table: "AspNetUsers",
+                type: "datetime(6)",
+                nullable: true);
+
+            migrationBuilder.AddColumn<string>(
+                name: "CalendarSubscriptionStamp",
+                table: "AspNetUsers",
+                type: "varchar(64)",
+                maxLength: 64,
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "CalendarSubscriptionCreatedAt",
+                table: "AspNetUsers");
+
+            migrationBuilder.DropColumn(
+                name: "CalendarSubscriptionStamp",
+                table: "AspNetUsers");
+        }
+    }
+}

src/Jiaowu.Api/Infrastructure/Persistence/Migrations/MySql/AppDbContextModelSnapshot.cs

@@ -3016,6 +3016,13 @@ namespace Jiaowu.Api.Infrastructure.Persistence.Migrations.MySql
                     b.Property<int>("AccessFailedCount")
                         .HasColumnType("int");
 
+                    b.Property<DateTime?>("CalendarSubscriptionCreatedAt")
+                        .HasColumnType("datetime(6)");
+
+                    b.Property<string>("CalendarSubscriptionStamp")
+                        .HasMaxLength(64)
+                        .HasColumnType("varchar(64)");
+
                     b.Property<Guid?>("CollegeId")
                         .HasColumnType("char(36)");