Close the metadata gap: the outer kind-4497 envelope was signed with the
sender's real key, so a coordinator/relay could see exactly who was talking.
- buildEnvelope now signs each envelope with a fresh ephemeral key (NIP-59
style) — the coordinator never learns the sender.
- Authorship moves inside the ciphertext: a new v2 sealed payload
(`nip44-group-v2`) carries a fully-signed inner author-proof event (kind 4498)
bound to the crew via an `a` tag. openGroupMessage verifies the signature,
author, content match, and group binding — so authorship stays unforgeable and
a proof can't be replayed into another crew.
- Transport trusts the verified v2 proof and surfaces the real sender; legacy
v1 envelopes remain readable (outer-key binding) for back-compat.
- NIP.md updated with the v2 format + an honest note on the residual
verbatim-replay caveat (full replay/forward-secrecy hardening lands with MLS).
Scope decision: kept to crew chat only. Regular 1:1/group DMs already use NIP-17
gift wrap (ephemeral keys, sealed per recipient) and have no coordinator, so
they need no change and stay idiot-proof.
Co-authored-by: shakespeare.diy <assistant@shakespeare.diy>
The crew coordinator is no longer just a pointer — when a crew configures one,
the Chat tab runs through it for real.
- src/lib/cordn: clean transport/crypto split so an MLS (ts-mls) upgrade is a
drop-in swap of the crypto layer only.
- types.ts: CordnMessage/CordnEndpoint + envelope kind 4497 + app tag.
- crypto.ts: sealGroupMessage/openGroupMessage — real NIP-44 group encryption
(per-recipient sealing), the exact seam MLS encrypt-to-epoch slots into.
- client.ts: buildEnvelope/publishEnvelope/fetchGroupMessages with per-group
cursor ordering and ciphertext→author sender binding (anti-spoof).
- endpoint.ts: resolve a crew's `coordinator` to a usable relay endpoint
(wss/ws direct; https falls back to the ContextVM relay).
- useCordnChat: fetch-then-poll hook mirroring the NIP-17 chat API.
- CrewChat: uses Cordn when the crew has a coordinator, NIP-17 fallback
otherwise; header badge shows the active transport (Cordn vs Private).
- CrewCoordinatorCard: reflects that private chat is live.
- NIP.md: document envelope kind 4497, delivery (fetch-then-poll + cursors),
the nip44-group sealed content, and the honest crypto→MLS seam.
Real encryption, real coordinator routing, non-breaking (fallback intact),
with the MLS ratchet as a clearly-marked next step.
Co-authored-by: shakespeare.diy <assistant@shakespeare.diy>
