What happened?
RFC 9114 Section 4.2 ：“Characters in field names MUST be converted to lowercase prior to their encoding. A request or response that contains uppercase characters in field names MUST be treated as malformed.”
xquic在发送端(xqc_h3_request_make_name_lowercase)检测到大写字段名时，仅将其转换为小写后继续发送，而不是拒绝该请求。在接收端，QPACK解码后完全没有对字段名进行大写检测。RFC要求包含大写字符的请求/响应必须视为格式错误，而非静默修正。
xqc_h3_request.c:484-530 xqc_h3_request_make_name_lowercase() 仅用于发送端; 接收端无大写检测
nghttp3_http.c:530-563 nghttp3_http_on_header() 在 http_check_nonempty_header_name 中检测大写字母(A-Z在VALID_HD_NAME_CHARS中标记为-1)，返回 NGHTTP3_ERR_MALFORMED_HTTP_HEADER
在接收端添加字段名大写检测，发现大写字母时返回H3_MESSAGE_ERROR流错误
Steps To Reproduce
Information and Steps to reproduce the behavior.
Relevant log output
What happened?
RFC 9114 Section 4.2 ：“Characters in field names MUST be converted to lowercase prior to their encoding. A request or response that contains uppercase characters in field names MUST be treated as malformed.”
xquic在发送端(xqc_h3_request_make_name_lowercase)检测到大写字段名时，仅将其转换为小写后继续发送，而不是拒绝该请求。在接收端，QPACK解码后完全没有对字段名进行大写检测。RFC要求包含大写字符的请求/响应必须视为格式错误，而非静默修正。
xqc_h3_request.c:484-530 xqc_h3_request_make_name_lowercase() 仅用于发送端; 接收端无大写检测
nghttp3_http.c:530-563 nghttp3_http_on_header() 在 http_check_nonempty_header_name 中检测大写字母(A-Z在VALID_HD_NAME_CHARS中标记为-1)，返回 NGHTTP3_ERR_MALFORMED_HTTP_HEADER
在接收端添加字段名大写检测，发现大写字母时返回H3_MESSAGE_ERROR流错误
Steps To Reproduce
Information and Steps to reproduce the behavior.
Relevant log output