Two coordinated changes:
1. Desktop client gets a functional Messages section and working pairing
flow, putting it at feature parity with mobile for the v2.2.0 line.
2. Server + both clients teach each other to use the sender's master
Ed25519 (not just their X25519) to address conversations, so a peer
writing from a different linked device still rolls into the same chat.
This is the "new API logic" the desktop scaffold was waiting on.
Server (node/api_relay.go, cmd/node/main.go):
* /relay/inbox items now carry `sender_ed25519_pub` alongside the
per-device `sender_pub`. Empty string for pre-v2.2.0 senders.
* WS `inbox` push summary also includes `sender_ed25519_pub`, so the
client can skip the refetch when the envelope plainly isn't for
the chat they're watching.
* Both existing tests pass.
Mobile client:
* lib/types.ts Envelope grew `sender_ed25519_pub`; fetchInbox normalises
it (default '') for older nodes.
* hooks/useGlobalInbox matches contacts by (master Ed25519 OR legacy
X25519) so an incoming message from a peer's desktop reuses the
existing chat instead of creating a duplicate placeholder.
* hooks/useMessages now takes an optional `contactMasterEd25519` and
exposes a matchesChat() predicate; WS inbox handler uses it too to
avoid spurious refetches.
* chats/[id].tsx passes `contact.address` (master) along with x25519.
Desktop client — all new:
* src/lib/crypto.ts — tweetnacl hex/base64 helpers, generateKeyFile,
encryptMessage/decryptMessage, signBase64, shortAddr. Same signatures
as the mobile lib; uses Chromium's window.crypto, no expo-crypto dep.
* src/lib/tx.ts — buildTransferTx / buildLinkDeviceTx / buildUnlinkDeviceTx
+ submitTx + humanizeTxError, canonical-bytes identical to mobile.
* src/lib/relay.ts — fetchInbox, sendEnvelope, resolveRecipientKeys
(multi-device fan-out with legacy identity.x25519 fallback).
* src/lib/store.ts — zustand state gets messages{}, unread{},
activeChat.
* src/lib/storage.ts — per-chat cache via localStorage (500-msg cap).
* src/hooks/useInboxPoll — 4s polling loop, addresses conversations
by master Ed25519, bumps unread unless chat is active.
* src/sections/messages/* — ChatList (sorted tiles, unread badges),
Conversation (auto-scroll messages + composer + fan-out send,
Enter-to-send / Shift+Enter for newline), EmptyConversation.
* src/auth/Pair.tsx — 6-digit code + device key screen, polls inbox
for a handshake envelope, assembles the KeyFile on arrival.
* Welcome.tsx: Pair button now actually routes to <Pair>; imports
generateKeyFile from lib/crypto (was inlined).
docs/ROADMAP.md delta: alpha5 row flipped to done inline. Alpha6
(feed + wallet) and rc1 (contacts + devices UI + profile) still
pending.
ce11a13874