feat(common): MNP 0.2 — liveness, and chat history read the way it is written

2026-08-16T13:28:53Z

`get_messages` pages forward from the oldest message. That is the right shape for "what happened since I last looked" and the wrong one for opening a conversation, and the browser asked it for `since=0, limit=200` — so a group with more than two hundred messages showed its first two hundred and the exchange anyone came for was unreachable. Demonstrated on 300 messages: the newest was simply absent from the answer. `get_recent` and `get_before` page backwards, cursored on the row id rather than the timestamp. Nothing makes a `time.time()` float unique, and a cursor on a value two rows can share eventually skips a message or repeats it. PING/PONG covers liveness on an already-open channel: a DataChannel whose peer vanished without closing still reads as connected, and nothing noticed until a real request hung. It is not a discovery mechanism — opening a connection to ping costs a full ICE/DTLS handshake, measured at 0.6-7 s across two ISPs — so presence in the group list comes from the hub's registry instead. Both additions are backward compatible: an 0.1 peer sends no `before` and is answered with the newest page, which is what it wanted. Co-Authored-By: Claude Opus 5

meshbay.git/packages/meshbay-node/tests/test_chat_pagination.py, branch v0.9.0

feat(common): MNP 0.2 — liveness, and chat history read the way it is written