v0.5 — Instance peering (federation v1)
Manuel's peering proposal (2026-07-26, Peering-Idea.drawio): every Cairn instance stays standalone and scales for itself, but any two instances can form an explicit, admin-established peering and stream files to each other's users. Trust model: each instance generates a per-peer key and hands it to the other admin OUT OF BAND (email/vault/pastebin — deliberately not our problem); admins register peer name + received key + URL; the wire carries only key hashes. The target instance verifies the key pair AND that the addressed recipient exists locally before any bytes flow. End users just see a dropdown of admin-registered peers on "Send to…". Differentiator: sovereign instance-to-instance transfer without a central broker — "nobody does that shit right now." Timing: Kubernetes Gateway API became usable this year, making public gRPC routing realistic.
