Statically link SQLite into hydra-node binary
Add `static-sqlite` to the static-libs overlay (built with `--disable-shared`) and point the `direct-sqlite` pkgconfig at it. This embeds libsqlite3 directly into the binary for both native and musl64 builds, so Docker images do not need libsqlite3.so at runtime — fixing the container crash-loop seen in the network-test CI workflow.