test: add comprehensive integration tests

- Add 19 integration tests covering:
  - Bucket operations (create, delete)
  - Object operations (upload, download, copy, move, delete)
  - Multipart upload (boundary conditions, large files)
  - Recursive operations (delete, copy)
  - Edge cases (special characters, empty files, deep paths)
  - Error handling (not found, bucket not found)
  - Presigned URLs

Tests require a running S3-compatible server (MinIO/RustFS) and are
guarded by the 'integration' feature flag.

Author: overtrue

.cursor/plans/rc_cli_开发计划_b21bc588.plan.md

@@ -46,19 +46,19 @@ graph TB
         Main[main.rs]
         Commands[commands/]
     end
-    
+
     subgraph core_layer [Core Layer]
         Client[S3Client Wrapper]
         Config[Config Manager]
         Alias[Alias Manager]
     end
-    
+
     subgraph infra_layer [Infrastructure]
         Output[Output Formatter]
         Progress[Progress Bar]
         Error[Error Handler]
     end
-    
+
     Main --> Commands
     Commands --> Client
     Commands --> Config
@@ -381,4 +381,4 @@ rc sql --query "SELECT * FROM s3object WHERE age > 20" minio/bucket/data.csv
 
 ## 风险与缓解
 
-| 风险 | 缓解措施 ||------|----------|| aws-sdk-s3 API 变化 | 锁定版本，关注 changelog || 大文件传输内存问题 | 使用流式传输，分片上传 |
+| 风险 | 缓解措施 ||------|----------|| aws-sdk-s3 API 变化 | 锁定版本，关注 changelog || 大文件传输内存问题 | 使用流式传输，分片上传 |