fix: 修复从库初始化时密码解密错误

问题：从配置文件读取的密码是明文，但代码尝试对它进行解密，导致解密失败

修复：
- 将 masterPasswordDecrypted 改为 masterPasswordPlain
- 从配置文件读取的密码是明文，不需要解密
- 只有从数据库读取的密码才是加密的，需要解密

datai-system/src/main/java/com/datai/system/service/impl/SysDatasourceConfigServiceImpl.java

@@ -464,14 +464,14 @@ public class SysDatasourceConfigServiceImpl implements ISysDatasourceConfigServi
             throw new RuntimeException("数据源名称已存在：" + environmentCode);
         }
 
-        String masterPasswordDecrypted = decryptPassword(masterPassword);
+        String masterPasswordPlain = masterPassword;
 
         Connection connection = null;
         Statement statement = null;
         SysDatasourceConfig slaveConfig = null;
 
         try {
-            connection = DriverManager.getConnection(masterUrl, masterUsername, masterPasswordDecrypted);
+            connection = DriverManager.getConnection(masterUrl, masterUsername, masterPasswordPlain);
             statement = connection.createStatement();
 
             String createDbSql = String.format("CREATE DATABASE `%s` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci", slaveDbName);
@@ -504,7 +504,7 @@ public class SysDatasourceConfigServiceImpl implements ISysDatasourceConfigServi
             log.info("[从库创建] 数据源配置写入成功, ID: {}", slaveConfig.getId());
 
             String slaveJdbcUrl = buildJdbcUrl(slaveConfig);
-            dynamicDataSourceManager.addDynamicDataSource(slaveConfig.getDsName(), slaveJdbcUrl, slaveConfig.getUsername(), masterPasswordDecrypted);
+            dynamicDataSourceManager.addDynamicDataSource(slaveConfig.getDsName(), slaveJdbcUrl, slaveConfig.getUsername(), masterPasswordPlain);
             log.info("[从库创建] 数据源注册成功: {}", slaveConfig.getDsName());
 
             switchDataSource(slaveConfig.getDsName());