pilot.md: step-by-step for connecting two households (link-agnostic),
measurement protocol M0-M4 (link baseline, uplink baseline, pooled,
concurrent downloads, sn-fair Soll/Ist comparison), safety/legal
checklist, and a results section to be filled after the pilot.
Cross-linked from Home, documentation README, roadmap, architecture
and server README; roadmap marks sn-fair v0 done.
