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

client_transport.go

@@ -174,28 +174,37 @@ func (c *ClientCommon) dispatchTransportPayloadFast(payload []byte, release func
 		}
 		return
 	}
-	if c.tryDispatchBorrowedBulkTransportPayload(payload) {
-		if release != nil {
-			release()
+	plain, plainRelease, err := c.decryptTransportPayloadPooled(payload, release)
+	if err != nil {
+		if c.showError || c.debugMode {
+			fmt.Println("client decode transport payload error", err)
 		}
 		return
 	}
-	owned := append([]byte(nil), payload...)
-	if release != nil {
-		release()
+	if c.tryDispatchBorrowedTransportPlain(plain, plainRelease) {
+		return
 	}
 	if dispatcher == nil {
 		now := time.Now()
-		if err := c.dispatchInboundTransportPayload(owned, now); err != nil && (c.showError || c.debugMode) {
+		err := c.dispatchInboundTransportPlain(plain, now)
+		if plainRelease != nil {
+			plainRelease()
+		}
+		if err != nil && (c.showError || c.debugMode) {
 			fmt.Println("client decode envelope error", err)
 		}
 		return
 	}
+	owned := plain
+	if plainRelease != nil {
+		owned = append([]byte(nil), plain...)
+		plainRelease()
+	}
 	c.wg.Add(1)
 	if !dispatcher.Dispatch(clientInboundDispatchSource(), func() {
 		defer c.wg.Done()
 		now := time.Now()
-		if err := c.dispatchInboundTransportPayload(owned, now); err != nil && (c.showError || c.debugMode) {
+		if err := c.dispatchInboundTransportPlain(owned, now); err != nil && (c.showError || c.debugMode) {
 			fmt.Println("client decode envelope error", err)
 		}
 	}) {