feat: implement ADR-029/030/031 — RuvSense multistatic sensing + field model + RuView fusion

12,126 lines of new Rust code across 22 modules with 285 tests:

ADR-029 RuvSense Core (signal crate, 10 modules):
- multiband.rs: Multi-band CSI frame fusion from channel hopping
- phase_align.rs: Cross-channel LO phase rotation correction
- multistatic.rs: Attention-weighted cross-node viewpoint fusion
- coherence.rs: Z-score per-subcarrier coherence scoring
- coherence_gate.rs: Accept/PredictOnly/Reject/Recalibrate gating
- pose_tracker.rs: 17-keypoint Kalman tracker with re-ID
- mod.rs: Pipeline orchestrator

ADR-030 Persistent Field Model (signal crate, 7 modules):
- field_model.rs: SVD-based room eigenstructure, Welford stats
- tomography.rs: Coarse RF tomography from link attenuations (ISTA)
- longitudinal.rs: Personal baseline drift detection over days
- intention.rs: Pre-movement prediction (200-500ms lead signals)
- cross_room.rs: Cross-room identity continuity
- gesture.rs: Gesture classification via DTW template matching
- adversarial.rs: Physically impossible signal detection

ADR-031 RuView (ruvector crate, 5 modules):
- attention.rs: Scaled dot-product with geometric bias
- geometry.rs: Geometric Diversity Index, Cramer-Rao bounds
- coherence.rs: Phase phasor coherence gating
- fusion.rs: MultistaticArray aggregate, fusion orchestrator
- mod.rs: Module exports

Training & Hardware:
- ruview_metrics.rs: 3-metric acceptance test (PCK/OKS, MOTA, vitals)
- esp32/tdm.rs: TDM sensing protocol, sync beacons, drift compensation
- Firmware: channel hopping, NDP injection, NVS config extensions

Security fixes:
- field_model.rs: saturating_sub prevents timestamp underflow
- longitudinal.rs: FIFO eviction note for bounded buffer

README updated with RuvSense section, new feature badges, changelog v3.1.0.

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

rust-port/wifi-densepose-rs/crates/wifi-densepose-ruvector/src/lib.rs

@@ -28,3 +28,4 @@
 
 pub mod mat;
 pub mod signal;
+pub mod viewpoint;