fix: 外部审查 8 项修复 + 国密 TLS 按需回退

- UserAgent 默认值回退 + 注册 -ua flag (#2)
- README 编译命令 main.go → . (#3)
- README 版本号同步 rc.1 (#4)
- Client.go gmtls stdout 劫持删除 (#5)
- ms17010 smb1GetResponse size<32 越界 panic (#6)
- SSH 拨号超时统一 ModuleTimeout (#8)
- AddPorts 死字段删除 (#9)
- 国密 TLS 按需回退：标准 TLS 握手失败时仅在错误为
  cipher/protocol 不兼容时尝试国密，跳过超时/拒绝等连接级错误

webscan/lib/eval_test.go

@@ -1238,7 +1238,7 @@ func TestDoRequestSkipsNilGMTLSFallback(t *testing.T) {
 	}()
 
 	ClientNoRedirect = &http.Client{Transport: roundTripFunc(func(*http.Request) (*http.Response, error) {
-		return nil, errors.New("standard tls failed")
+		return nil, errors.New("tls: handshake failure")
 	})}
 	ClientNoRedirectGM = nil
 
@@ -1261,7 +1261,7 @@ func TestDoRequestReplaysBodyForGMTLSFallback(t *testing.T) {
 
 	ClientNoRedirect = &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
 		_, _ = io.ReadAll(req.Body)
-		return nil, errors.New("standard tls failed")
+		return nil, errors.New("tls: handshake failure")
 	})}
 
 	var gotBody string