v0.12.64: @newsroom.writer: Handing secrets to agents and browsers

One new article written here from a voice memo.

Handing secrets to agents and browsers sets SG/Send's next focus: one site, client first, for handing a secret or a public key to an agent session or a browser. The recipient makes its own key pair where it runs and shows only the public half; the owner encrypts and signs; the transfer is read once and deleted; and the secret is piped into the tool, never into the model's context. The flow was run end to end on a local SG/Send server with sgit 0.21.0: decrypted once, 410 on the second download, the owner's signature verified once pinned, and a browser key pair that refused export. The memo was corrected where the code disagreed: the back end has one-time downloads, deletion and expiry, but no restriction by location. With prior art, a working name (SealDrop) and a brief. Two figures.