fix: NEWKEYS 后重置序列号为 0（加密上下文切换）

src/ssh/packet.ts

@@ -79,6 +79,10 @@ export class SSHPacketParser {
     return this.seqNum;
   }
 
+  resetSeqNum(): void {
+    this.seqNum = 0;
+  }
+
   getBufferLength(): number {
     return this.buffer.length;
   }

src/worker/ssh-session.ts

@@ -220,6 +220,8 @@ export class SSHSession {
         await this.writeSocket(packet);
         console.log('[KEX] NEWKEYS sent');
 
+        this.seqNumSend = 0;
+        this.packetParser.resetSeqNum();
         await this.enableEncryption();
         console.log('[KEX] Encryption enabled');