fix(notify): 根治低带宽控制面阻塞与传输写入卡死

- 为控制消息增加优先级、公平调度、队列字节预算和自适应批处理
- 支持可取消的写门等待，收紧 shared/dedicated bulk、stream 和 Reply 写入边界
- 修复 bulk reset/close、连接 handoff 和安全 profile 切换时序
- 保留旧取消与超时错误契约，新增阶段化 TransportSendError
- 增加 ReplyCtx、ReplyObjCtx、写超时配置及黑洞连接和竞态回归测试

client.go

@@ -28,6 +28,7 @@ type ClientCommon struct {
 	maxReadTimeout                time.Duration
 	maxWriteTimeout               time.Duration
 	keyExchangeFn                 func(c Client) error
+	linkMu                        sync.RWMutex
 	linkFns                       map[string]func(message *Message)
 	defaultFns                    func(message *Message)
 	msgEn                         func([]byte, []byte) []byte
@@ -39,6 +40,7 @@ type ClientCommon struct {
 	handshakeRsaPubKey            []byte
 	SecretKey                     []byte
 	transportProtection           atomic.Pointer[transportProtectionProfile]
+	inboundTransitionProfile      atomic.Pointer[transportProtectionProfile]
 	peerAttachSecurity            atomic.Pointer[peerAttachSecurityState]
 	securityBootstrap             transportProtectionProfile
 	securitySteady                transportProtectionProfile