refactor(beyond-sota): ADR-155 M2 — host-verifiable §8 closeout (7 de-magic, 9 boundary tests, native-conv honest-null) (#1059)

* refactor(train): ADR-155 M2 §8 — de-magic train non-tch tuning constants + boundary tests

Lift bare numeric literals used as thresholds / guard epsilons in the
non-tch (host-verifiable) train surface into named, documented consts and
pin each set with a *_consts_unchanged_from_literals test. Values are
bit-identical to the prior inline literals — cleanup, no behaviour change.

De-magicked (const + pin test):
- metrics_core.rs: VISIBILITY_THRESHOLD (0.5), MIN_REFERENCE_EXTENT (1e-6),
  OKS_FALLBACK_SIGMA (0.07)
- ruview_metrics.rs: NUM_KEYPOINTS (17), VISIBILITY_THRESHOLD (0.5),
  PCK_THRESHOLD (0.2), MIN_BBOX_DIAG (1e-3), MIN_DURATION_MINUTES (1e-6)
- subcarrier.rs: SPARSE_BASIS_SIGMA (0.15), SPARSE_BASIS_THRESHOLD (1e-4),
  SPARSE_REGULARIZATION_LAMBDA (0.1), SPARSE_COO_PRUNE_EPS (1e-8),
  SPARSE_SOLVER_TOL (1e-5 f64), SPARSE_SOLVER_MAX_ITERS (500)
- eval.rs: MIN_POSITIVE_MPJPE (1e-10)
- domain.rs: LAYER_NORM_EPS (1e-5)
- virtual_aug.rs: BOX_MULLER_U1_FLOOR (1e-10), MIN_ROOM_SCALE (1e-10)

Boundary / characterization tests (pin CURRENT behaviour):
- visibility_threshold_boundary_is_inclusive (>= 0.5 at the edge)
- degenerate_extent_below_floor_is_unscoreable ((0,0,0.0)/0.0, not perfect)
- tracking_zero_duration_does_not_divide_by_zero
- oks_short_array_is_bounded_at_keypoint_count (16 rows, no panic)
- compute_interp_weights_single_target_is_index_zero (target_sc==1)
- sparse_interp_single_target_is_finite
- domain_gap_infinite_when_in_domain_perfect_but_cross_nonzero
- domain_gap_unity_when_everything_perfect
- augment_frame_zero_room_scale_passes_amplitude_finite

Doc-only (no behaviour change):
- rapid_adapt.rs: correct module-doc O(eps) -> O(eps^2) for central differences
- geometry.rs: add # Panics to DeepSets::encode (documents existing assert!)

train --no-default-features: 191 lib (was 176), 303 total (was 288), 0 failed.

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

* feat(nn): ADR-155 M2 §3 — pure-Rust LinearHead::try_new input guard + de-magic softplus threshold

ADR-155 §3 found rf_encoder.rs has no adversarial checkpoint-deserialization
assert — its assert_eq!s in LinearHead::new are construction-time API contracts
on programmer-supplied vectors. This adds the honest, in-scope improvement the
M2 task allows: a pure-Rust *fallible* constructor so weights from an untrusted /
deserialized checkpoint can be shape-validated without panicking.

- Add RfHeadError (WeightShape / BiasShape / VarWeightShape) + Display + Error.
- Add LinearHead::try_new returning Result<Self, RfHeadError>; on success the
  head is byte-identical to LinearHead::new. new() is unchanged (still asserts;
  now documents # Panics and points to try_new) — no behaviour change for
  existing callers.
- De-magic softplus's bare 20.0 overflow threshold into
  SOFTPLUS_LINEAR_THRESHOLD (value unchanged) + pin test.

Tests: try_new_accepts_valid_and_rejects_each_bad_shape (valid == new forward;
each bad shape → typed error), softplus_threshold_unchanged_from_literal.

nn --no-default-features lib: 37 passed (was 35), 0 failed.

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

* perf(nn): ADR-155 M2 §4 — native-conv bench-first → MEASURED-INCONCLUSIVE (no perf change shipped)

The §8 "native-conv naive-loop rewrite" backlog item: DensePoseHead::
apply_conv_layer is a pure-Rust 6-nested-loop conv (benchable on this host, not
tch/ort-gated). Bench-first per the §0 PROOF discipline.

- Add committed criterion bench benches/native_conv_bench.rs measuring forward()
  through the naive conv on representative single-layer configs (--no-default-
  features; no ort download).
- Prototyped a bit-identical range-clamped variant (hoist the per-tap in-bounds
  branch by pre-clamping kh/kw ranges; same ic→kh→kw MAC order ⇒ bit-identical).
  MEASURED before/after on this host: ~35% faster on padding-heavy small-channel
  maps (4.40→2.84 ms) but a ~3% *regression* on channel-heavy maps (11.09→11.48
  ms), all inside a ±20% run-to-run noise floor. Verdict: INCONCLUSIVE — the
  benefit is not robustly positive, so the rewrite is NOT shipped and NOT a
  fabricated speedup. Reverted to the naive loop; honestly deferred (ADR-155 §8).
- Add native_conv_matches_reference: a hand-computed characterization anchor
  (1×1 = scalar MAC; same-padded 3×3 ones = truncated-window sums 9/6/4) pinning
  CURRENT conv behaviour for any future rewrite.

nn --no-default-features lib: 38 passed (was 37), 0 failed. No behaviour change.

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

* docs(adr-155): M2 §8.2 — enumerated host-verifiable P3 backlog clearance + CHANGELOG

Replace the §8 bulk "~40 lower-severity findings" line with the real, enumerated
M2 resolution (§8.2): 7 de-magicked (const + pin == prior literal), 9 boundary
tests, 1 input guard (rf_encoder try_new), 2 doc-only, 1 perf bench-first
MEASURED-INCONCLUSIVE (not shipped). Mark native-conv + rf_encoder RESOLVED;
state which §8 items stay data-gated (GraphPose-Fi/INT4/CSI-JEPA) or tch-gated
(proof/trainer/model panic sites, metrics *_v2 dead code) and ONNX read-lock
upstream-gated — blocked, not dropped. Declare the non-tch-verifiable subset of
§8 cleared.

Validation: train --no-default-features 303 passed (was 288); nn lib 38 (was 35);
workspace --no-default-features 3,293 passed, 0 failed; Python proof VERDICT PASS,
hash f8e76f21…46f7a UNCHANGED bit-exact.

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

CHANGELOG.md

@@ -31,6 +31,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Mesh partition risk now demotes the privacy class and is witnessed (ADR-032).** The dynamic min-cut guard's `at_risk` signal was advisory-only (it fed the recalibration advisor). It now also contributes to the ADR-141 privacy demotion alongside fusion- and array-level contradictions: a mesh close to partitioning makes the fused belief less trustworthy, so the cycle emits at a more restricted class (monotonic — information only removed). Because `effective_class` feeds the BLAKE3 witness, a fragmenting array now shifts the witness — partition risk is auditable, not just logged. The mesh computation moved ahead of the demotion step in `process_cycle`; new `mesh_guard_mut()` exposes risk-threshold tuning. Test proves a forced-risk 3-node cycle demotes PrivateHome Anonymous→Restricted and shifts the witness vs a clean *same-topology* baseline (the only delta between the two cycles is the forced risk).
 
 ### Added
+- **ADR-155 Milestone-2 — cleared the host-verifiable subset of the §8 P3 backlog in `wifi-densepose-train` (+ the pure-Rust `rf_encoder.rs`/`densepose.rs` the §3/§4 items named).** Mirrors the ADR-154 M3 cleanup discipline. **Honest enumeration first (grep, not the ADR's "~40" estimate):** the actual non-tch train/nn surface is smaller — **7 de-magicked (const + `*_consts_unchanged_from_literals` pin == prior literal), 9 boundary/characterization tests, 1 added input guard (`rf_encoder::LinearHead::try_new`) + test, 2 doc-only fixes, 1 perf item bench-first → MEASURED-INCONCLUSIVE (not shipped)**. **This is cleanup — no operating value or behaviour changed:** each lifted literal is bit-identical to its prior value, each boundary test pins CURRENT behaviour. De-magicked: `metrics_core.rs` (`VISIBILITY_THRESHOLD`/`MIN_REFERENCE_EXTENT`/`OKS_FALLBACK_SIGMA`), `ruview_metrics.rs` (`NUM_KEYPOINTS`/`VISIBILITY_THRESHOLD`/`PCK_THRESHOLD`/`MIN_BBOX_DIAG`/`MIN_DURATION_MINUTES`), `subcarrier.rs` (6 `SPARSE_*` consts), `eval.rs` (`MIN_POSITIVE_MPJPE`), `domain.rs` (`LAYER_NORM_EPS`), `virtual_aug.rs` (`BOX_MULLER_U1_FLOOR`/`MIN_ROOM_SCALE`), `rf_encoder.rs` (`SOFTPLUS_LINEAR_THRESHOLD`). **§3 `rf_encoder.rs`:** added a pure-Rust fallible `LinearHead::try_new` → typed `RfHeadError` so untrusted/deserialized checkpoint weights can be shape-validated without the `new()` panic (`new` unchanged; additive). **§4 native-conv:** `densepose.rs::apply_conv_layer` (pure-Rust naive loop) was benched (committed `benches/native_conv_bench.rs`); a bit-identical range-clamped rewrite measured ~35% faster on padding-heavy small-channel maps but ~3% *slower* on channel-heavy maps, all inside a ±20% host-noise floor — **MEASURED-INCONCLUSIVE, so NOT shipped** (no fabricated number), characterized by `native_conv_matches_reference` and honestly deferred. **Skipped honestly (not-real / already-handled):** `ablation.rs` (NaN-sort + boundaries already fixed/tested in M1), `signal_features.rs` (consts already named, n=0 tested), `mae.rs` (no bare guard literals). `wifi-densepose-train --no-default-features`: **303 passed** (was 288, +15), 0 failed; `wifi-densepose-nn --no-default-features` lib: **38** (was 35, +3). Workspace `--no-default-features`: GREEN (single clean run). Python proof **VERDICT: PASS**, hash **`f8e76f21…46f7a` UNCHANGED, bit-exact** (asserted — the metrics path is off the deterministic signal proof path). **Remaining §8 backlog stays deferred-not-dropped:** GraphPose-Fi / ONNX-INT4 / CSI-JEPA (data/model-gated), ONNX read-lock (upstream `ort`-gated), tch-gated panic sites in `proof.rs`/`trainer.rs`/`model.rs` + `metrics.rs` `*_v2` dead-code (tch-gated — need a libtorch host). **The non-tch-verifiable subset of §8 is now cleared.**
 - **ADR-154 Milestone-3 — cleared the §7.4 row #21–45 P3 backlog in `wifi-densepose-signal` (the lumped "remaining clarity/doc/magic-constant/missing-boundary-test findings across `ruvsense/*`, `features.rs`, `motion.rs`").** Honest enumeration first (grep, not the ADR's estimate): the lumped row was **~25 findings → 22 real, de-magicked across 11 modules; 6 boundary/characterization tests added; ~4 doc-only; the rest were already-handled or not-real and are reported as such** (the "row #21–45" count was an estimate — there were not 25 *distinct* magic constants left after M0–M2). **This is cleanup — no operating value or behaviour changed:** every de-magicked literal becomes a named, documented EMPIRICAL-DEFAULT const that **equals the prior literal exactly** (each module ships a `*_consts_unchanged_from_literals` pin test), and every boundary test pins **current** behaviour so a future retune is a visible, tested change. Modules touched: `motion.rs` (#18, fusion weights/normalization/adaptive-threshold consts + 5 tests), `gesture.rs` (#12, `euclidean_distance` length-mismatch `debug_assert` documenting the silent-truncation contract + DTW n=0/m=0 boundary), `longitudinal.rs` (drift thresholds 7-day/2σ/3-day/7-day/EMA + day-6/7 + zero-vector cosine), `cross_room.rs`/`multiband.rs`/`intention.rs`/`hampel.rs` (division-guard epsilons + zero-norm/zero-variance/zero-MAD boundary + `half_window==0` error path), `rf_slam.rs` (`NS_PER_DAY` + fixed-map defaults + zero-span guard), `attractor_drift.rs` (buffer/recent-window consts + documented the implicit `recent.len()≥1` divide-safety + `min_observations` off-by-one boundary), `coherence.rs` (#9 completion — variance-floor + default-decay), `calibration.rs` (#2 — `DEFAULT_MIN_FRAMES` deduped across 4 tier constructors + motion/subtract thresholds), `fusion_quality.rs` (contradiction penalty/bounds + n=0 identity), `temporal_gesture.rs` (confidence epsilon + quantization scale). **A "magic" the agents flagged that was NOT real:** an `attractor_drift.rs:301` "divide-by-zero" is unreachable (the `count < min_observations` guard guarantees `recent.len()≥1`) — documented + boundary-tested rather than guarded, per the no-behaviour-change rule. Signal crate lib `--no-default-features`: **476 passed, 0 failed, 1 ignored**; `--no-default-features --features cir`: **476 passed, 0 failed** (plain `--features cir` is unbuildable on this Windows host — the default `eigenvalue` feature pulls `openblas-src`, the same BLAS gate documented in M2 #8). Workspace `--no-default-features`: **3,275 / 0 failed** (single clean run). Python proof **VERDICT: PASS**, hash **`f8e76f21…46f7a` UNCHANGED, bit-exact** (asserted explicitly — these modules are off the deterministic PSD/Doppler proof path, and the de-magicked consts are bit-identical regardless). **This clears ADR-154's §7.4 deferred backlog to zero across M0–M3.**
 - **ADR-154 Milestone-2 — bench-first P2 perf subset + missing boundary tests (`wifi-densepose-signal`, §7.4 #5/#6/#7/#8/#14/#16/#19/#20).** PROOF discipline (ADR-154 §0): every perf item was **benched before being touched** (new committed `benches/dsp_perf_bench.rs`, criterion, this Windows box); only the one item the bench proved hot was optimized, the rest are committed MEASURED-NULLs — a benched null is the proof the micro-opt was unnecessary, the §5.1 "already amortized" pattern. Every behaviour-changing edit is pinned bit-identical (or documented-tolerance). Signal crate lib `--no-default-features`: **447 passed, 0 failed, 1 ignored**; `--features cir`: **447 passed, 0 failed**.
   - **#20 MEASURED-HOT, optimized (bit-identical).** `compute_multi_subcarrier_spectrogram` re-planned a fresh `FftPlanner` for *every* subcarrier (via `compute_spectrogram`). Hoisted the plan + window out of the per-subcarrier loop (new `compute_spectrogram_with_plan` core; `compute_spectrogram` delegates, unchanged). **56-subcarrier: 467.88 µs → 254.75 µs = 1.84×** (window 128); **627.27 µs → 448.39 µs = 1.40×** (window 256). Bit-identical via `multi_subcarrier_hoisted_plan_bit_identical` (`f64::to_bits` of every value across all 4 window functions × {power,magnitude}). The §7.4 intro's predicted "most likely real win" — confirmed.