v1.10.0

Keep Signal connected — a new switch in Settings → Signal, off by default.

Until now the Signal connection lived only as long as the app's process, and nothing owned
that process. It existed because you opened the app, or a text arrived, or the phone
booted; when Android reclaimed it the connection went too, and the next Signal message
waited until something woke the app again. That it worked in the background at all was an
accident: Desktop Sync runs a foreground service, which kept the process alive and the
Signal connection with it. With Desktop Sync off, nothing did.

With the switch on, a service holds the connection open and messages arrive as they are
sent. The price is a permanent notification — quiet, no badge, with a Stop on it that turns
the setting off rather than leaving the next reboot to bring it back.

With it off, which is how it ships, there is no notification and Signal catches up every
fifteen minutes and whenever you open the app. That bounds how long a message can sit
unseen rather than leaving it to chance.

On a phone chosen partly for not having notifications on it, that seemed a choice to leave
with the person holding the phone rather than make for them.

Both halves are re-established whenever the app's process starts, including the one Android
creates at boot — so Signal comes back on its own after a flat battery.

Full Changelog: v1.9.0...v1.10.0