feat(notify): 重构通信内核并补齐 stream/bulk/record/transfer 能力

- 引入 LogicalConn/TransportConn 分层，ClientConn 保留兼容适配层
  - 新增 Stream、Bulk、RecordStream 三条数据面能力及对应控制路径
  - 完成 transfer/file 传输内核与状态快照、诊断能力
  - 补齐 reconnect、inbound dispatcher、modern psk 等基础模块
  - 增加大规模回归、并发与基准测试覆盖
  - 更新依赖库

envelope.go

@@ -0,0 +1,184 @@
+package notify
+
+import (
+	"b612.me/notify/internal/timeutil"
+	crand "crypto/rand"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sync/atomic"
+)
+
+type EnvelopeKind uint8
+
+const (
+	EnvelopeSignal EnvelopeKind = iota
+	EnvelopeSignalAck
+	EnvelopeStreamData
+	EnvelopeFileMeta
+	EnvelopeFileChunk
+	EnvelopeFileEnd
+	EnvelopeFileAbort
+	EnvelopeAck
+)
+
+type Envelope struct {
+	Kind   EnvelopeKind
+	ID     uint64
+	Body   []byte
+	Stream StreamPacket
+	File   FilePacket
+}
+
+type StreamPacket struct {
+	StreamID string
+	Chunk    []byte
+}
+
+type FilePacket struct {
+	FileID   string
+	Name     string
+	Size     int64
+	Mode     uint32
+	ModTime  int64
+	Offset   int64
+	Chunk    []byte
+	Checksum string
+	Error    string
+	Stage    string
+}
+
+func wrapTransferMsgEnvelope(msg TransferMsg, enFn func(interface{}) ([]byte, error)) (Envelope, error) {
+	body, err := enFn(msg)
+	if err != nil {
+		return Envelope{}, err
+	}
+	return Envelope{
+		Kind: EnvelopeSignal,
+		ID:   msg.ID,
+		Body: body,
+	}, nil
+}
+
+func unwrapTransferMsgEnvelope(env Envelope, deFn func([]byte) (interface{}, error)) (TransferMsg, error) {
+	if env.Kind != EnvelopeSignal {
+		return TransferMsg{}, errors.New("envelope kind is not signal")
+	}
+	data, err := deFn(env.Body)
+	if err != nil {
+		return TransferMsg{}, err
+	}
+	msg, ok := data.(TransferMsg)
+	if !ok {
+		return TransferMsg{}, errors.New("invalid signal envelope payload")
+	}
+	return msg, nil
+}
+
+func newSignalAckEnvelope(signalID uint64) Envelope {
+	return Envelope{
+		Kind: EnvelopeSignalAck,
+		ID:   signalID,
+	}
+}
+
+func newStreamDataEnvelope(streamID string, chunk []byte) Envelope {
+	return Envelope{
+		Kind: EnvelopeStreamData,
+		Stream: StreamPacket{
+			StreamID: streamID,
+			Chunk:    chunk,
+		},
+	}
+}
+
+func newFileMetaEnvelope(fileID string, fileName string, fileSize int64, checksum string, mode uint32, modTime int64) Envelope {
+	return Envelope{
+		Kind: EnvelopeFileMeta,
+		File: FilePacket{
+			FileID:   fileID,
+			Name:     filepath.Base(fileName),
+			Size:     fileSize,
+			Mode:     mode,
+			ModTime:  modTime,
+			Checksum: checksum,
+		},
+	}
+}
+
+func newFileChunkEnvelope(fileID string, offset int64, chunk []byte) Envelope {
+	return Envelope{
+		Kind: EnvelopeFileChunk,
+		File: FilePacket{
+			FileID: fileID,
+			Offset: offset,
+			Chunk:  chunk,
+		},
+	}
+}
+
+func newFileEndEnvelope(fileID string) Envelope {
+	return Envelope{
+		Kind: EnvelopeFileEnd,
+		File: FilePacket{
+			FileID: fileID,
+		},
+	}
+}
+
+func newFileAbortEnvelope(fileID string, stage string, offset int64, errMsg string) Envelope {
+	return Envelope{
+		Kind: EnvelopeFileAbort,
+		File: FilePacket{
+			FileID: fileID,
+			Stage:  stage,
+			Offset: offset,
+			Error:  errMsg,
+		},
+	}
+}
+
+func newFileAckEnvelope(fileID string, stage string, offset int64, errMsg string) Envelope {
+	return Envelope{
+		Kind: EnvelopeAck,
+		File: FilePacket{
+			FileID: fileID,
+			Stage:  stage,
+			Offset: offset,
+			Error:  errMsg,
+		},
+	}
+}
+
+var fileIDSerial uint64
+
+func buildFileID(fileName string) string {
+	base := fileIDBaseName(fileName)
+	ts := uint64(timeutil.NowUnixNano())
+	pid := uint64(os.Getpid())
+	seq := atomic.AddUint64(&fileIDSerial, 1)
+	rnd := uint64(randomFileIDSuffix())
+	return fmt.Sprintf("%s-%x-%x-%x-%x", base, ts, pid, seq, rnd)
+}
+
+func fileIDBaseName(fileName string) string {
+	base := sanitizeFileName(filepath.Base(fileName))
+	switch base {
+	case "", ".", "/", "\\":
+		return "unnamed"
+	default:
+		return base
+	}
+}
+
+func randomFileIDSuffix() uint32 {
+	var buf [4]byte
+	if _, err := crand.Read(buf[:]); err == nil {
+		return binary.BigEndian.Uint32(buf[:])
+	}
+	seq := atomic.LoadUint64(&fileIDSerial)
+	mix := uint64(timeutil.NowUnixNano()) ^ (seq << 1) ^ uint64(os.Getpid())
+	return uint32(mix ^ (mix >> 32))
+}