Send to riskmandate-agent-collab through an append lane

Chosen by the editor of record on 25 September in place of a member's clone: the newsroom holds one write-only append token and the vault owner's public key, and never the vault key.

Waiting on the vault's owner (the request is on the briefing page for riskmandate.ai): the token (to the editor of record, then NEWSROOM_APPEND_TOKEN in the environment), the public key bundle and its fingerprint, the server's base URL, and who the postmaster is.

Then: tools/relay.py send --lane (build the .eml, sgit pki encrypt to the key, POST with stdlib urllib, mark sent); the key bundle and fingerprint in data/relay.json and on the briefing page; brief 1's message sent first; issue 046 closed as not taken.

Done when: message 001 is sent through the lane and the owner confirms it landed in mail/mailroom/mailbox.riskmandate/.

Done, 25 September

The postmaster opened the lane (reply filed at briefings/riskmandate.ai/inbox/2026-09-25__re-open-an-append-lane-for-the-newsroom.md): dev.send.sgraph.ai, front door sha256:8f8132b304423587, configure replaces anchors (this newsroom's is the only one), @Cowork is the postmaster. The editor of record handed over the token; it lives only in the environment of the command that sends. This newsroom made its own key pair (sha256:9b69885b35612bdd, signing sha256:f791a1cfb957d58f) and published the bundle. tools/relay.py lane sent the first message, encrypted and signed, to @Cowork: the lane answered {"ok": true}. Brief 1 was not sent again: @Cowork had relayed it as 003-relay-editor-briefs-042-045.eml. Confirmation that it landed will come as a reply.