This requires POST and (small file) upload support from the
PSGI/Plack web server. CGI.pm is currently not supported with
this feature.
We'll serve everything git can handle by default for performance
in the general case.
To avoid introducing cognitive overhead for sysadmins managing
existing HTTP backends, we do not introduce new configuration
directives.
Thus, setting http.uploadpack=false in the relevant git config
file for each public-inbox (ssoma) git repo will disable smart
HTTP for CPU/memory-constrained systems.
Technically we could support http.receivepack to allow posting
messages to a public-inbox over HTTP(S), but that breaks
the public-inbox model of encouraging users to Cc: everyone.
Again, we encourage users to Cc: everyone to reduce the chance
of a public-inbox becoming a centralized point of
failure/censorship.