refactor: 项目重构为 bschclassmanage 包结构，修复启动/CORS/路由问题

- 根包 com.bestsch.classicalchinese 重命名为 com.bestsch.bschclassmanage
- 修复 CORS 启动失败：allowCredentials=true 时 allowedOrigins 不能含 "*"，
  23 个 Controller 的 @CrossOrigin 改用语义等价的 originPatterns
- 修复 /api/* 与 /oapi/* 接口 404：API_PATH/OAPI 常量去掉尾斜杠，
  消除 Spring Boot 2.7 PathPattern 下的双斜杠(/api//subject/) 导致的匹配失败
- UserSysRoleArgumentResolver 增加从 URL 参数 currentrole 回退解析(便于本地调试)，
  原请求头 currentrole 注入方式保持不变

src/main/java/com/bestsch/bschclassmanage/entity/SchInfo.java

@@ -0,0 +1,40 @@
+package com.bestsch.bschclassmanage.entity;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import javax.persistence.*;
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+import javax.validation.constraints.Size;
+
+/**
+ * 学校班级表
+ */
+@AllArgsConstructor
+@NoArgsConstructor
+@Data
+@Entity
+@Table(name = "sch_info")
+public class SchInfo {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @NotNull(groups = BaseSchsystem.Update.class, message = "更新时ID不能为空")
+    private Integer id;
+
+    @Column(name = "sch_id", nullable = false)
+    private Integer schId;
+
+    @Column(name = "name", length = 255, nullable = false)
+    private String name;
+
+    @Column(name = "sch_serid", length = 50)
+    private String schSerId;
+
+    @Column(name = "sort")
+    private Integer sort;
+
+    public @interface Update {}
+}