HTTP2: Respect SETTINGS_MAX_HEADER_LIST_SIZE

SETTINGS_MAX_HEADER_LIST_SIZE (0x6):
This advisory setting informs a peer of the maximum size of header list that the sender is prepared to accept, in octets. The value is based on the uncompressed size of header fields, including the length of the name and value in octets plus an overhead of 32 octets for each header field.

For any given request, a lower limit than what is advertised MAY be enforced. The initial value of this setting is unlimited.

The issue names no files or tests. Start by locating the HTTP/2 SETTINGS processing and header-list validation entry points, then trace how the advertised limit is applied. Done means enforcing the uncompressed header-list size limit while preserving the initial unlimited value described in the issue.

Written by the indexing model from the issue text.