feat(transport): 完成安全架构拆分并收口 stream/bulk 传输优化

- 新增 managed/external/nested 三种传输保护模式
  - 新增 peer attach 显式认证、抗重放、channel binding 和可选前向保密协商
  - 明确单连接注入与可重拨连接源的语义边界
  - 禁止 ConnectByConn 场景下 dedicated bulk 走 sidecar，auto 模式自动回退 shared
  - 修正 dedicated attach 在 bootstrap/steady profile 切换下的处理逻辑
  - 优化 shared bulk super-batch 与批量 framed write 路径
  - 降低 stream/bulk fast path 的复制和分发损耗
  - 补齐 benchmark、回归测试、运行时快照和 README 文档

clienttype.go

@@ -26,6 +26,8 @@ type Client interface {
 	BulkOpenTuning() BulkOpenTuning
 	SetBulkDedicatedAttachConfig(BulkDedicatedAttachConfig)
 	BulkDedicatedAttachConfig() BulkDedicatedAttachConfig
+	SetPeerAttachSecurityConfig(PeerAttachSecurityConfig) error
+	PeerAttachSecurityConfig() PeerAttachSecurityConfig
 	SetFileReceiveDir(dir string) error
 	send(msg TransferMsg) (WaitMsg, error)
 	sendEnvelope(env Envelope) error