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

client_legacy_security.go

@@ -0,0 +1,44 @@
+package notify
+
+import (
+	"b612.me/starcrypto"
+	"errors"
+	"fmt"
+	"math/rand"
+	"time"
+)
+
+// Deprecated: ExchangeKey drives the legacy RSA-based key exchange flow.
+// Prefer UseModernPSKClient.
+func (c *ClientCommon) ExchangeKey(newKey []byte) error {
+	pubKey, err := starcrypto.DecodeRsaPublicKey(c.handshakeRsaPubKey)
+	if err != nil {
+		return err
+	}
+	newSendKey, err := starcrypto.RSAEncrypt(pubKey, newKey)
+	if err != nil {
+		return err
+	}
+	data, err := c.sendWait(TransferMsg{
+		ID:    19961127,
+		Key:   "sirius",
+		Value: newSendKey,
+		Type:  MSG_KEY_CHANGE,
+	}, time.Second*10)
+	if err != nil {
+		return err
+	}
+	if string(data.Value) != "success" {
+		return errors.New("cannot exchange new aes-key")
+	}
+	c.SecretKey = newKey
+	time.Sleep(time.Millisecond * 100)
+	return nil
+}
+
+// Deprecated: aesRsaHello is the legacy RSA-based key exchange bootstrap.
+func aesRsaHello(c Client) error {
+	newAesKey := []byte(fmt.Sprintf("%d%d%d%s", time.Now().UnixNano(), rand.Int63(), rand.Int63(), "b612.me"))
+	newAesKey = []byte(starcrypto.Md5Str(newAesKey))
+	return c.ExchangeKey(newAesKey)
+}