refactor: 根包由 com.bestsch.bschclassmanage 重命名为 com.yunhai.bschclassmanage

- git mv src/main/java/com/bestsch/bschclassmanage -> src/main/java/com/yunhai/bschclassmanage
- 255 个 Java 文件的 package/import 同步替换为 com.yunhai.bschclassmanage
- pom.xml 项目 groupId 设为 com.yunhai（与外部依赖 com.bestsch:bsch-* 无关，未改动）
- IDE 缓存 workspace.xml 路径同步更新（外部依赖坐标 com.bestsch:bsch-* 保持不动）

src/main/java/com/yunhai/bschclassmanage/ClassicalchineseApplication.java

@@ -0,0 +1,19 @@
+package com.yunhai.bschclassmanage;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.scheduling.annotation.EnableAsync;
+import org.springframework.scheduling.annotation.EnableScheduling;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+
+@SpringBootApplication
+@EnableTransactionManagement
+@EnableAsync
+@EnableScheduling
+public class ClassicalchineseApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ClassicalchineseApplication.class, args);
+    }
+
+}