Follow-up to the peer-hives removal: docs/web-ui/dashboard.md drops
the whole "P33R H1V3S" section + its stale #peers hash and tab-strip
mentions; docs/swarm/README.md's runtime-effects list and
cross-references point at swarm-ui's roster page instead. Nix comments
in hive-c0re/environment.nix, swarm.nix and swarm-wireguard.nix that
described HYPERHIVE_PEERS/certFingerprint as dashboard-consumed are
updated to say what's actually still true (agent identity only).
Deliberately NOT removed: the `certFingerprint` nix option itself.
It has no remaining Rust consumer, but deleting a documented,
potentially already-set option is a bigger, breaking change than
removing dead display code — flagged in docs/swarm/README.md with a
note instead of silently dropped, so an operator or reviewer can make
that call explicitly rather than have it made for them here.
8c8f0e2758