sock: read full request across segments (fix POST body behind proxy)

handle_client_read did a single read() and assumed the whole request
(headers + POST body) arrived in one packet. Behind a reverse proxy
(Traefik) the body is forwarded in a separate TCP segment, so the form
params (event/nick/tmpid/...) were never parsed: logins silently no-op'd,
the frameset was served with tmpid= (empty), and every frame hit
'Session: Could not find session' -> 502 in all frames.

Now accumulate into c_buf across re-arms of the read event (track i_buf_len
in the context), drain non-blocking until EAGAIN, and for POST wait until
the headers AND the full Content-Length body are present before parsing.
EOF/empty and hard read errors are handled without crashing.

0 files changed, 0 insertions, 0 deletions