Clients had no way to learn the gateway attachment ceilings, so external
clients hardcoded guesses that drifted from server enforcement. Publish the
two unconditional decoded-size ceilings on hello-ok policy.attachments from
one shared resolver so advertised values cannot drift from the parser.
MIME acceptance and per-message counts stay server-side: they depend on the
entrypoint, the resolved model, and payload sniffing, so they cannot be stated
once per connection.
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 17d6c355-8948-4b48-a936-e08b1c8806ef
b6c4b2d55b
