feat(contract): 新增合同余额功能及重构文件管理

重构合同文件管理逻辑，增加错误处理和日志记录
新增ContractBalance实体、Repository和VO类
完善Voable接口文档和实现规范
更新项目架构文档和数据库设计
修复SmbFileService的连接问题
移动合同相关TabSkin类到contract包
添加合同文件重建任务的WebSocket支持

server/src/main/java/com/ecep/contract/service/SmbFileService.java

@@ -399,6 +399,10 @@ public class SmbFileService implements DisposableBean {
             try {
                 // 获取连接
                 connectionInfo = getConnectionInfo(hostname);
+                if (connectionInfo == null) {
+                    log.error("Failed to get SMB connection for host: {}", hostname);
+                    break;
+                }
 
                 // 从session池获取session
                 sessionInfo = connectionInfo.peekSession();
@@ -407,8 +411,13 @@ public class SmbFileService implements DisposableBean {
                     // 获取认证上下文
                     AuthenticationContext authContext = getAuthenticationContext(hostname);
                     // 创建新session并添加到池中
-                    sessionInfo = connectionInfo.createSession(authContext);
-                    log.debug("Created new SMB session for host: {}", hostname);
+                    try {
+                        sessionInfo = connectionInfo.createSession(authContext);
+                        log.debug("Created new SMB session for host: {}", hostname);
+                    } catch (SMBRuntimeException ex) {
+                        log.error("Failed to create SMB session for host: {}, maxTrys:{}", hostname, maxTrys, ex);
+                        continue;
+                    }
                 } else {
                     log.debug("Reusing SMB session for host: {}", hostname);
                 }
@@ -421,22 +430,16 @@ public class SmbFileService implements DisposableBean {
                     log.debug("Returned SMB session to pool for host: {}", hostname);
 
                 } catch (SMBRuntimeException e) {
-                    sessionInfo.close();
-                    throw e;
+                    try {
+                        sessionInfo.close();
+                    } catch (IOException ignored) {
+                    }
+                    log.error("Failed to execute SMB operation for host: {}, maxTrys:{}", hostname, maxTrys, e);
+                    continue;
                 } finally {
 
                 }
-
                 break;
-            } catch (TransportException e) {
-                log.warn("TransportException occurred while trying to connect to host: {}. Retrying...", hostname);
-                // 延迟1秒
-                try {
-                    Thread.sleep(1000);
-                } catch (InterruptedException ex) {
-                    Thread.currentThread().interrupt();
-                }
-                continue;
             } catch (IOException e) {
                 // 如果操作失败且连接信息存在，检查连接状态
                 if (connectionInfo != null) {
@@ -501,7 +504,7 @@ public class SmbFileService implements DisposableBean {
      * @throws IOException 如果检查失败
      */
     public boolean exists(SmbPath smbPath) throws IOException {
-        return executeSmbOperation(smbPath, (share, path) -> {
+        Object result = executeSmbOperation(smbPath, (share, path) -> {
             try {
                 FileAllInformation info = share.getFileInformation(path);
                 if (info.getStandardInformation().isDirectory()) {
@@ -516,6 +519,10 @@ public class SmbFileService implements DisposableBean {
                 throw e;
             }
         });
+        if (result != null) {
+            return (boolean) result;
+        }
+        return false;
     }
 
     /**