feat(adr-185): P3 MAT bindings (wifi_densepose.mat) + parity harness

Bind the ADR-024 MAT (Mass Casualty Assessment Tool) disaster-survivor
detection + START triage surface into the wheel behind a gated [mat]
extra / Cargo `mat` feature, mirroring the upstream disaster/ML gating.
Also adds the [sota] superset extra (aether+meridian+mat).

Surface (bound against the REAL code at HEAD, not the ADR wishlist):
- DisasterType (9 variants) / TriageStatus (5, START) enums
- DisasterConfig (builder-backed, continuous_monitoring forced off)
- DisasterResponse: initialize_event / add_zone / push_csi_data /
  scan_once / survivors / survivors_by_triage
- Survivor (id, triage_status, confidence, location, latest_vitals)
- VitalSignsReading (breathing/heartbeat rate, movement, confidence)
- ScanZone.rectangle / ScanZone.circle
push_csi_data + scan_once are GIL-released.

Honest deviations from ADR section 3.4 (documented in module header):
- ADR proposed adding a Rust-side sync scan_once() (section 11.3). That was
  UNNECESSARY: the public async start_scanning() runs exactly one
  scan_cycle and returns when continuous_monitoring == false. The binding
  forces that flag off and drives one cycle on a private current-thread
  tokio runtime -- NO change to wifi-densepose-mat.
- scan_cycle requires an active event + Active zone, which the ADR surface
  omitted; initialize_event + add_zone are bound as required additions.
- Survivor.vital_signs is a *history* in the real code; bound as
  Survivor.latest_vitals -> Optional[VitalSignsReading].
- DisasterType has 9 variants at HEAD (adds Landslide/MineCollapse/
  Industrial/TunnelCollapse); all bound.

Parity (section 4.1, release-blocking): committed fixture mat_input.json
(synthetic breathing-modulated CSI stream) -> native Rust reference
(tests/mat_parity.rs, drives DisasterResponse directly) locks
tests/golden/mat_result.sha256 over a canonical
`count=<K>;triage_priorities=<sorted>` string (survivor UUIDs/timestamps
excluded as non-deterministic); pytest (tests/test_mat.py) runs the same
stream through the binding and asserts the identical hash. Both detect
exactly 1 survivor, triage Delayed. Honest: synthetic fixture proves
binding==native path equality, NOT live detection accuracy.

Verified:
  cargo test --features mat --test mat_parity -> 2/2 pass
  maturin develop --features mat + pytest tests/test_mat.py -> 7/7 pass
  default cargo build clean, 0 mat/tokio refs in the default dep graph.

WHEEL-SIZE FINDING (ADR-185 section 9): default-features=false drops MAT's
`api` (axum) and `ruvector` features, but MAT still carries NON-optional
tokio (rt/sync/time), wifi-densepose-nn (ort/ONNX + reqwest/hyper),
rustfft, geo, ndarray. So a [mat] wheel exceeds the ADR-117 section 5.4
<=5 MB budget -- same leaf-crate-hoist follow-up as AETHER/MERIDIAN. The
default wheel is untouched (feature-gated).

python/src/lib.rs

@@ -20,6 +20,8 @@ mod bindings {
     #[cfg(feature = "aether")]
     pub mod aether;
     pub mod bfld;
+    #[cfg(feature = "mat")]
+    pub mod mat;
     #[cfg(feature = "meridian")]
     pub mod meridian;
     pub mod keypoint;
@@ -51,6 +53,8 @@ fn build_features() -> Vec<&'static str> {
     feats.push("p6-aether-bindings"); // ADR-185 P1 — AETHER contrastive embeddings
     #[cfg(feature = "meridian")]
     feats.push("p6-meridian-bindings"); // ADR-185 P2 — MERIDIAN domain generalization
+    #[cfg(feature = "mat")]
+    feats.push("p6-mat-bindings"); // ADR-185 P3 — MAT disaster survivor detection
     feats
 }
 
@@ -106,5 +110,10 @@ fn wifi_densepose_native(m: &Bound<'_, PyModule>) -> PyResult<()> {
     #[cfg(feature = "meridian")]
     bindings::meridian::register(m)?;
 
+    // ADR-185 P3 — MAT disaster-survivor detection + START triage. Gated
+    // behind `mat`, mirroring the upstream disaster/ML stack gating.
+    #[cfg(feature = "mat")]
+    bindings::mat::register(m)?;
+
     Ok(())
 }