Add ENV GOMEMLIMIT=1536MiB to the runtime stage so the Go runtime keeps a
1.5 GiB soft heap limit. runuser preserves it the way it already does
XDG_DATA_HOME, so the routewatch process inherits it.
Add a Memory section to the README describing the budget (Go 1.5 GiB soft,
SQLite 640 MiB pool cache and 1.5 GiB hard heap, ~0.2 GiB other), the
required 5 GiB container limit, how to override GOMEMLIMIT, what happens at
each limit, and the DEBUG=routewatch System stats line. Every sentence
matches the behaviour already merged to next.
Model: opus-4-8