Notes and photos were stuck on one machine. A small Go/Postgres backend
stores each group's payload under a code that doubles as the shared
secret, so a second Mac just needs the code — no account or login.
Applying a remote change must not push it straight back, otherwise the
two Macs would bump the version back and forth forever, so payloads are
fingerprinted and identical ones are skipped.
💘 Generated with Crush
Assisted-by: Crush:kimi-k3
