Add two debug/profiling tools to 05-custom.sh:
- gops: live process diagnostics (list Go processes, dump stacks, force GC)
- benchstat: statistically sound benchmark comparison via pprof
Both tools baked into /usr/local/bin at build time.
Build verified: go1.26.3, all 19 tools confirmed on PATH.
- rootfs/root/docker/setup/05-custom.sh: add gops and benchstat installs
rootfs/root/docker/setup/05-custom.sh