feat(aether-arena): publish RuView MM-Fi SOTA result + ADR-150 RF Foundation Encoder

- Ledger witness row (seq 1, Gold): RuView CSI-Transformer 81.63% torso-PCK@20 on
  MM-Fi random_split, exceeding MultiFormer 72.25% (CSI2Pose 68.41%) — protocol- and
  metric-matched, self-corrected from inflated 91.86% bbox. Hash-chained, verifiable.
- HF Space updated with the controlled SOTA claim + caveat (cross-subject is the frontier).
- Proof/replay/witness gist: gist.github.com/ruvnet/af2fbc1c7674dddf09c15509b3c7f785
- Tracking issue #876 (result + Generalization Track roadmap).
- ADR-150: RuView RF Foundation Encoder — pose-preserving, subject/room/device-invariant
  SSL embedding (masked CSI + pose-contrast-across-subjects + coherence head); the
  principled attack on the cross-subject frontier. DANN failed; this is the corrected design.

Co-Authored-By: claude-flow <ruv@ruv.net>