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

bulk_buffer_release_test.go

@@ -1,12 +1,27 @@
 package notify
 
 import (
+	"b612.me/stario"
 	"context"
 	"errors"
+	"math"
+	"net"
+	"sync"
 	"testing"
 	"time"
 )
 
+type bulkReleaseTrackingConn struct {
+	net.Conn
+	started chan struct{}
+	once    sync.Once
+}
+
+func (c *bulkReleaseTrackingConn) Write(p []byte) (int, error) {
+	c.once.Do(func() { close(c.started) })
+	return c.Conn.Write(p)
+}
+
 func TestBulkOwnedChunkReleaseAfterRead(t *testing.T) {
 	bulk := newBulkHandle(context.Background(), newBulkRuntime("buffer-release-read"), clientFileScope(), BulkOpenRequest{
 		BulkID: "buffer-release-read",
@@ -117,3 +132,41 @@ func TestBulkReadDoesNotBlockOnAsyncWindowRelease(t *testing.T) {
 		}
 	}
 }
+
+func TestLegacyBulkReleaseHonorsBulkCancellation(t *testing.T) {
+	client := NewClient().(*ClientCommon)
+	if err := UseModernPSKClient(client, integrationSharedSecret, integrationModernPSKOptions()); err != nil {
+		t.Fatal(err)
+	}
+	stopCtx, stopFn := context.WithCancel(context.Background())
+	defer stopFn()
+	pipeLeft, right := net.Pipe()
+	left := &bulkReleaseTrackingConn{Conn: pipeLeft, started: make(chan struct{})}
+	defer left.Close()
+	defer right.Close()
+	queue := stario.NewQueueCtx(stopCtx, 4, math.MaxUint32)
+	client.setClientSessionRuntime(newClientSessionRuntime(left, stopCtx, stopFn, queue, 1))
+	client.markSessionStarted()
+
+	bulk := newBulkHandle(context.Background(), nil, "test", BulkOpenRequest{
+		BulkID:          "legacy-release",
+		DataID:          1,
+		FastPathVersion: bulkFastPathVersionV1,
+		ChunkSize:       4,
+		WindowBytes:     4,
+		MaxInFlight:     1,
+	}, 0, nil, nil, 0, nil, nil, nil, nil, clientBulkReleaseSender(client))
+	bulk.maybeSendWindowRelease(4, true)
+	select {
+	case <-left.started:
+	case <-time.After(time.Second):
+		t.Fatal("legacy release did not enter physical write")
+	}
+
+	bulk.finalize()
+	select {
+	case <-bulk.releaseWorkerDone:
+	case <-time.After(150 * time.Millisecond):
+		t.Fatal("legacy bulk release worker ignored bulk cancellation while its send was blocked")
+	}
+}