Let the daemon receive docker stop's signal itself (closes #33)

entrypoint.sh now switches to the routewatch user (UID 1000) with setpriv instead of runuser. setpriv replaces itself with the daemon, so the daemon is the container's main process and receives docker stop's signal itself. runuser stayed in between, passed the signal on and killed the daemon 2 seconds later, so every stop ended with exit 143. The daemon now gets the whole wait the caller allows, up to its own 60-second limit, and a clean stop exits 0. Taking ownership of the state directory and the MALLOC_ARENA_MAX check still run as root first.

Not fixed here: a stop while the feed is flowing can still panic (#34).

Model: opus-5-5

TODO.md

@@ -23,6 +23,11 @@ runs make check on main.
 
 # Completed Steps
 
+- 2026-09-28: `docker stop` no longer kills the daemon 2 seconds after the
+  stop signal: the entrypoint switches to the `routewatch` user with
+  `setpriv` instead of `runuser`, so the daemon receives the signal itself
+  and gets the whole wait `docker stop` allows, up to its own 60-second
+  limit (closes #33)
 - 2026-09-28: ready to run under upaas: a set but invalid `PORT`,
   `XDG_DATA_HOME` or `MALLOC_ARENA_MAX` stops the start, the health
   check follows `PORT`, README "Running under upaas" section (closes