docs(research): add beyond-SOTA series index with validation results; changelog

README index ties the 5 research docs together with the session's
measured validation evidence: 2,797 workspace tests / 0 failed, Python
proof PASS (bit-exact), and paired pre/post criterion CIR benchmarks.

https://claude.ai/code/session_01MjBucx95K4BuUxZi8NWwRH

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- **RuView beyond-SOTA research series** (`docs/research/ruview-beyond-sota/`, 6 docs) — research-swarm output defining the beyond-SOTA bar and the path to it: system capability audit (role→crate maturity matrix, gap analysis, risk register), web-verified 2026 SOTA landscape per capability axis (incl. ratified IEEE 802.11bf-2025), 8-pillar target architecture on the ADR-136 contract spine (no rewrite), 6-layer benchmark/validation methodology (all 15 criterion bench targets inventoried; ADR-149 statistical protocol), and a determinism-safe optimization roadmap. Includes session validation evidence: 2,797 workspace tests / 0 failed, Python proof PASS (bit-exact), paired pre/post criterion runs.
+
+### Performance
+- **CIR estimator warm-start precompute** — the diagonal Tikhonov preconditioner `diag(Φ^H Φ)+λI` and its CSR matrix were rebuilt every frame although they depend only on Φ and λ (fixed at `CirEstimator::new`); now precomputed at construction (`ruvsense/cir.rs`). Bit-identical floats (summation order unchanged, witness chain unaffected). Measured: `cir_estimate/he40` −3.9% (p<0.01), multiband groups −1.2/−1.4%; smaller configs within container noise.
+- **RF tomography solver hoisting** — ISTA gradient buffer no longer allocated inside the 100-iteration loop, and the Frobenius Lipschitz bound moved from per-`reconstruct` to construction (`ruvsense/tomography.rs`). Bit-identical results.
+
 ### Fixed
 - **ESP32 edge heart rate no longer stuck at ~45 BPM / dropping wildly — #987.** The on-device HR estimator (`edge_processing.c`, `0xC5110002`) reported ~45 BPM regardless of true heart rate (Apple-Watch ground truth 87 BPM read as ~45) and swung frame-to-frame. Two root causes: (1) a hardcoded `sample_rate = 10.0f` that became wrong after #985's self-ping raised the CSI callback rate to a variable ~13–19 Hz — BPM scales as `assumed/actual × true`, so 87 read ~45 and the reading swung as CSI yield fluctuated; (2) the zero-crossing estimator locked onto a breathing harmonic (a 0.25 Hz breathing fundamental puts its 3rd harmonic at ~0.74 Hz ≈ 44 BPM inside the HR band). Fix: measure the real sample rate from inter-frame timestamps (used for BPM conversion + biquad re-tuning on >15% drift); replace the HR zero-crossing with an autocorrelation estimator that rejects breathing harmonics (driven by a robust autocorr breathing period); median-13 smooth the output. Hardware A/B (fixed vs unmodified control board, both `edge_tier=2`): control pegged 40–49 BPM; fixed reaches the true 88–91 BPM (vs 87 GT) and holds a stable physiological value (spread 59→0 for a steady subject). Known limitation: heavy subject motion still degrades the estimate (motion gating is a follow-up).
 - **Person count no longer leaks up to 10 in heuristic mode — addresses #894.** `field_bridge::occupancy_or_fallback` returned the eigenvalue-based `FieldModel::estimate_occupancy` count **unbounded** (its internal ceiling is 10), while the sibling estimators on the same single-link data — the perturbation-energy fallback right below it and `score_to_person_count` — both cap at 3 ("1-3 for single ESP32"). On noisy / under-calibrated CSI the eigenvalue count inflated, producing the "10 persons reported when 1 present" symptom (seen when `--model` fails to load and the server runs on heuristics). Bounded the eigenvalue path to the shared `MAX_SINGLE_LINK_OCCUPANCY` (3) so every estimator on one link agrees; genuine higher counts come from the multistatic fusion path, not a single-link covariance estimate.

docs/research/ruview-beyond-sota/README.md

@@ -0,0 +1,93 @@
+# RuView Beyond-SOTA Research Series
+
+Research swarm output (2026-06-09) defining what a beyond-state-of-the-art
+RuView implementation is, what the current system actually delivers, and the
+validation/benchmark/optimization evidence gathered in the same session.
+
+Produced by a 5-agent hierarchical research swarm (system reviewer, SOTA
+surveyor, architect, benchmark methodologist, performance analyst) plus a
+validation pass run against the working tree.
+
+## Documents
+
+| Doc | Scope | One-line takeaway |
+|-----|-------|-------------------|
+| [00-system-review.md](00-system-review.md) | Capability audit of the current engine | Signal layer is the deepest asset (`ruvsense/` ≈14.4k lines, 310 in-module tests); the model tier is the emptiest (no trained checkpoint in-tree); the live 20 Hz path is the main integration gap |
+| [01-sota-landscape-2026.md](01-sota-landscape-2026.md) | Published SOTA per capability axis (web-verified) | Defines the beyond-SOTA bar: 12-row capability → published SOTA → RuView-today → target table; IEEE 802.11bf-2025 is ratified and moves the moat up-stack |
+| [02-beyond-sota-architecture.md](02-beyond-sota-architecture.md) | Target architecture | 8 pillars (RF foundation encoder + UQ heads, differentiable RF forward model, RF-SLAM×WorldGraph loop, camera→RF distillation, swarm apertures, continual adaptation, deterministic WASM edge, NV fusion) — all landing inside existing crates, no rewrite (per ADR-136 §2.1) |
+| [03-benchmark-validation-methodology.md](03-benchmark-validation-methodology.md) | Test/validation/benchmark methodology | 6-layer validation pyramid; 15 criterion bench targets inventoried; `benchmark_baseline.json` is a live-capture anchor, not a criterion baseline; statistical protocol from ADR-149 (≥10 seeds, IQM, bootstrap CIs) |
+| [04-optimization-roadmap.md](04-optimization-roadmap.md) | Performance review + 90-day plan | ISTA CIR solver is the dominant latency hazard (~1.1 GFLOP/frame at HE40); exact zero-risk wins identified; WorldGraph grows unboundedly (no eviction) — a real bug-class |
+
+## Validation results (this session, 2026-06-09)
+
+All measured on this branch (`claude/ruview-beyond-sota-xgv8aq`), Linux
+container, `cargo test --workspace --exclude wifi-densepose-desktop
+--no-default-features` (the desktop crate needs GTK system libraries absent in
+the container; this is an environment limitation, not a code failure).
+
+| Layer | Command | Result |
+|-------|---------|--------|
+| L0 unit/integration | `cargo test --workspace --exclude wifi-densepose-desktop --no-default-features` | **154 suites, 2,797 passed, 0 failed** (pre-optimization baseline; re-run post-optimization also green) |
+| L1 deterministic proof | `python archive/v1/data/proof/verify.py` | **VERDICT: PASS** — hash `f8e76f21a0f9852b70b6d9dd5318239f6b20cbcb4cdd995863263cecdc446f7a` (bit-exact) |
+| L2 criterion (CIR) | `cargo bench -p wifi-densepose-signal --bench cir_bench --no-default-features --features cir` | Baselines captured pre/post optimization (below) |
+
+Known pre-existing issue (not introduced here): `cargo check -p
+wifi-densepose-mat --no-default-features` fails standalone with 101 serde
+feature-unification errors; it builds and passes inside `--workspace` runs.
+
+## Optimizations applied (this session)
+
+Two **exact** (bit-identical float results — summation order unchanged,
+witness chain unaffected) optimizations from the 04 roadmap's "zero-risk"
+tier were implemented and verified:
+
+1. **`cir.rs` warm-start precompute** — the diagonal Tikhonov preconditioner
+   `diag(Φ^H Φ) + λI` and its CSR matrix depend only on Φ and λ (fixed at
+   `CirEstimator::new`) but were rebuilt on every frame (O(K·G) pass + CSR
+   allocation). Moved to construction
+   (`crates/wifi-densepose-signal/src/ruvsense/cir.rs`,
+   `build_warm_start_system`).
+2. **`tomography.rs` solver hoisting** — the ISTA gradient `Vec` was
+   allocated inside the 100-iteration loop and the Frobenius Lipschitz bound
+   recomputed per `reconstruct` call; both hoisted
+   (`crates/wifi-densepose-signal/src/ruvsense/tomography.rs`).
+
+### Measured impact (criterion, paired pre/post baselines, same container)
+
+| Bench | Pre-opt | Post-opt | Change | Significant? |
+|-------|---------|----------|--------|--------------|
+| `cir_estimate/he40` | 12.34 ms | 11.86 ms | **−3.9 %** | yes (p < 0.01) |
+| `cir_multiband_3band` (30 ms group) | 30.16 ms | 29.72 ms | −1.4 % | yes (p < 0.01) |
+| `cir_multiband` (142 ms group) | 141.9 ms | 140.1 ms | −1.2 % | yes (p < 0.01) |
+| `cir_estimate/ht40` | 11.73 ms | 11.78 ms | +0.4 % | no (p = 0.28) |
+| `cir_estimate/he20` | 2.49 ms | 2.49 ms | −0.1 % | no (p = 0.85) |
+| `cir_estimate/ht20` | 2.48 ms | 2.58 ms | +3.8 % | noise — see note |
+
+Note on ht20: `cir_estimator_new/ht20` (construction, which now does strictly
+*more* work) also shows "+3 %", establishing a ≈3–4 % container noise floor;
+the ht20 estimate delta is within it. The honest summary: the warm-start
+precompute removes 1 of ~101 O(K·G) passes per frame, so the expected gain is
+≈1–4 % — consistent with what was measured. The dominant per-frame cost is
+the 100-iteration ISTA loop itself, which is exactly what the roadmap's
+flag-gated FFT-operator proposal (8–40× on the mat-vecs, requires witnessed
+hash regeneration) targets next.
+
+Correctness post-optimization: `wifi-densepose-signal` 456 tests green;
+`wifi-densepose-engine` 11/11 green including `cycle_is_deterministic` and
+`calibration_mismatch_demotes_and_witness_stable` (witness-chain stability).
+
+## Headline conclusions
+
+1. **"Beyond SOTA" is currently unfalsifiable** without a real-CSI
+   ground-truth benchmark — standing one up (per doc 03's acceptance table
+   and ADR-149's statistical protocol) is the highest-leverage next step.
+2. **The path is evolution, not rewrite**: all eight architecture pillars in
+   doc 02 land inside existing crates on the ADR-136 `Stage<I,O>`/`FrameMeta`
+   contract spine.
+3. **The biggest engineering gaps** are the live 20 Hz ingest path, a trained
+   RF encoder checkpoint, and WorldGraph retention/eviction — ahead of any
+   frontier capability work.
+4. **Determinism is the differentiator**: every optimization and new pillar
+   must preserve the witness chain; the advisory-vs-witnessed split (doc 02
+   §determinism) is the mechanism that lets frontier components in without
+   breaking it.