fix(adr-185): feature-gate MAT's ONNX ml module to cut [mat] wheel 8.4MB->2.0MB

Root cause (investigated, not assumed): the heavy deps in a [mat] wheel
were NOT on the survivor-detection/triage path the Python binding uses.
`wifi-densepose-mat` pulled `wifi-densepose-nn` as a NON-optional dep, and
nn's default `onnx` feature drags in `ort` (ONNX Runtime) + its
download/reqwest/hyper stack. But nn is used ONLY by mat's `src/ml/`
module (debris + vital-signs ONNX classifiers), which is an OPTIONAL
runtime enhancement: `DetectionPipeline.ml_pipeline` is `Option<_>`,
created only when `DetectionConfig::enable_ml` is set, and
`from_disaster_config` (the DisasterResponse path) never enables it. So
the ONNX stack was compiled-and-linked but never executed by the binding.

Fix = feature-gating (not a hoist — a hoist was unnecessary):
- `wifi-densepose-nn` made optional; new `ml` Cargo feature gates it.
- `default = [..., "ml"]` so existing consumers are unchanged; `api`
  implies `ml` (the REST surface exposes `ml_ready`).
- `#[cfg(feature = "ml")]` on the `ml` module, its crate-root + prelude
  re-exports, the `MatError::Ml` variant, and every ml touchpoint in
  detection/pipeline.rs (ml_config/ml_pipeline fields, constructor,
  process_zone enhancement block, enhance_with_ml/get_ml_results/
  initialize_ml/ml_ready/ml_pipeline accessors, update_config).
- Fixed a latent feature-unification bug surfaced by dropping nn:
  integration/hardware_adapter.rs uses `tokio::select!`, which needs
  `tokio/macros`. That was only satisfied transitively via nn; now
  declared explicitly on mat's own tokio dep so --no-default-features
  builds compile.

The ADR-185 [mat] wheel already depended on mat with
`default-features = false, features = ["std"]`, so no python/ change was
needed — dropping `ml` from the default now actually removes ort.

Measured (maturin build --release --features mat --strip):
  BEFORE (ml/ort in wheel): 8.4 MB  (over the ADR-117 §5.4 <=5 MB budget)
  AFTER  (ml gated off):    2.0 MB  (under budget) — 76% smaller

Verified:
  cargo build -p wifi-densepose-mat                         (default+ml)  OK
  cargo build -p wifi-densepose-mat --no-default-features --features std  OK
  cargo test --features mat --test mat_parity              2/2 pass
  maturin develop --features mat + pytest tests/test_mat.py 7/7 pass
  (same detection result: 1 survivor, triage Delayed — behavior-transparent)

python/Cargo.lock

@@ -4474,7 +4474,6 @@ dependencies = [
  "tracing",
  "uuid",
  "wifi-densepose-core",
- "wifi-densepose-nn",
  "wifi-densepose-signal",
 ]
 

v2/crates/wifi-densepose-mat/Cargo.toml

@@ -12,15 +12,25 @@ categories = ["science", "algorithms"]
 readme = "README.md"
 
 [features]
-default = ["std", "api", "ruvector"]
+default = ["std", "api", "ruvector", "ml"]
 ruvector = ["dep:ruvector-solver", "dep:ruvector-temporal-tensor"]
 std = []
+# ONNX-backed ML detection (debris + vital-signs classifiers). Pulls
+# `wifi-densepose-nn` (and, via its default `onnx` feature, the `ort`
+# ONNX Runtime + its download/reqwest stack) ONLY when enabled. The
+# survivor-detection/triage pipeline works without it (ML is an optional
+# enhancement, off unless `DetectionConfig::enable_ml`), so consumers that
+# don't need ONNX — e.g. the ADR-185 `wifi-densepose-py` `[mat]` wheel —
+# build `--no-default-features` and drop the entire ort/reqwest tree,
+# keeping the wheel within the ADR-117 §5.4 budget.
+ml = ["dep:wifi-densepose-nn"]
 # REST/WebSocket surface. Pulls the web stack (axum, futures-util) only when
 # enabled, and enables the `serde` FEATURE (not just `dep:serde`) so the
 # `cfg_attr(feature = "serde", ...)` derives on domain types are actually
 # active when the API is on (review finding 5: `api = ["dep:serde"]` enabled
 # the dependency but left every `feature = "serde"` cfg dead).
-api = ["serde", "dep:axum", "dep:futures-util"]
+# The REST surface exposes ML status (`ml_ready`), so `api` implies `ml`.
+api = ["ml", "serde", "dep:axum", "dep:futures-util"]
 # Real ESP32 serial CSI ingest. Pulls the native `serialport` crate (libudev on
 # Linux) only when enabled, so the default/no-default appliance build stays free
 # of native serial deps. With the feature OFF, the ESP32 serial *parser* still
@@ -36,14 +46,18 @@ serde = ["dep:serde", "chrono/serde", "geo/use-serde"]
 # Workspace dependencies
 wifi-densepose-core = { version = "0.3.0", path = "../wifi-densepose-core" }
 wifi-densepose-signal = { version = "0.3.0", path = "../wifi-densepose-signal", default-features = false }
-wifi-densepose-nn = { version = "0.3.0", path = "../wifi-densepose-nn" }
+wifi-densepose-nn = { version = "0.3.0", path = "../wifi-densepose-nn", optional = true }
 ruvector-solver = { workspace = true, optional = true }
 ruvector-temporal-tensor = { workspace = true, optional = true }
 
 # Async runtime — required by the core integration layer (UDP CSI receiver,
 # hardware adapter, scan loop in `DisasterResponse::start_scanning`), not just
 # the REST API, so it is deliberately NOT gated behind `api`.
-tokio = { version = "1.35", features = ["rt", "sync", "time"] }
+# `macros` is needed by `tokio::select!` in integration/hardware_adapter.rs.
+# It was previously satisfied only by feature-unification from the (now
+# optional) `wifi-densepose-nn` dep; declare it explicitly so a
+# `--no-default-features` build (the ADR-185 [mat] wheel) still compiles.
+tokio = { version = "1.35", features = ["rt", "sync", "time", "macros"] }
 async-trait = "0.1"
 
 # Web framework (REST API) — only compiled with the `api` feature.

v2/crates/wifi-densepose-mat/src/detection/pipeline.rs

@@ -8,6 +8,7 @@ use super::{
     MovementClassifier, MovementClassifierConfig,
 };
 use crate::domain::{ScanZone, VitalSignsReading};
+#[cfg(feature = "ml")]
 use crate::ml::{MlDetectionConfig, MlDetectionPipeline, MlDetectionResult};
 use crate::{DisasterConfig, MatError};
 
@@ -26,9 +27,10 @@ pub struct DetectionConfig {
     pub enable_heartbeat: bool,
     /// Minimum overall confidence to report detection
     pub min_confidence: f64,
-    /// Enable ML-enhanced detection
+    /// Enable ML-enhanced detection (requires the `ml` feature to have any effect)
     pub enable_ml: bool,
     /// ML detection configuration (if enabled)
+    #[cfg(feature = "ml")]
     pub ml_config: Option<MlDetectionConfig>,
 }
 
@@ -42,6 +44,7 @@ impl Default for DetectionConfig {
             enable_heartbeat: false,
             min_confidence: 0.3,
             enable_ml: false,
+            #[cfg(feature = "ml")]
             ml_config: None,
         }
     }
@@ -64,6 +67,7 @@ impl DetectionConfig {
     }
 
     /// Enable ML-enhanced detection with the given configuration
+    #[cfg(feature = "ml")]
     pub fn with_ml(mut self, ml_config: MlDetectionConfig) -> Self {
         self.enable_ml = true;
         self.ml_config = Some(ml_config);
@@ -71,6 +75,7 @@ impl DetectionConfig {
     }
 
     /// Enable ML-enhanced detection with default configuration
+    #[cfg(feature = "ml")]
     pub fn with_default_ml(mut self) -> Self {
         self.enable_ml = true;
         self.ml_config = Some(MlDetectionConfig::default());
@@ -147,12 +152,14 @@ pub struct DetectionPipeline {
     movement_classifier: MovementClassifier,
     data_buffer: parking_lot::RwLock<CsiDataBuffer>,
     /// Optional ML detection pipeline
+    #[cfg(feature = "ml")]
     ml_pipeline: Option<MlDetectionPipeline>,
 }
 
 impl DetectionPipeline {
     /// Create a new detection pipeline
     pub fn new(config: DetectionConfig) -> Self {
+        #[cfg(feature = "ml")]
         let ml_pipeline = if config.enable_ml {
             config.ml_config.clone().map(MlDetectionPipeline::new)
         } else {
@@ -164,12 +171,14 @@ impl DetectionPipeline {
             heartbeat_detector: HeartbeatDetector::new(config.heartbeat.clone()),
             movement_classifier: MovementClassifier::new(config.movement.clone()),
             data_buffer: parking_lot::RwLock::new(CsiDataBuffer::new(config.sample_rate)),
+            #[cfg(feature = "ml")]
             ml_pipeline,
             config,
         }
     }
 
     /// Initialize ML models asynchronously (if enabled)
+    #[cfg(feature = "ml")]
     pub async fn initialize_ml(&mut self) -> Result<(), MatError> {
         if let Some(ref mut ml) = self.ml_pipeline {
             ml.initialize().await.map_err(MatError::from)?;
@@ -178,6 +187,7 @@ impl DetectionPipeline {
     }
 
     /// Check if ML pipeline is ready
+    #[cfg(feature = "ml")]
     pub fn ml_ready(&self) -> bool {
         self.ml_pipeline.as_ref().is_none_or(|ml| ml.is_ready())
     }
@@ -210,13 +220,23 @@ impl DetectionPipeline {
             // `buffer` guard dropped here
         };
 
-        // If ML is enabled and ready, enhance with ML predictions
+        // If ML is enabled and ready, enhance with ML predictions (only
-        let enhanced_reading = if self.config.enable_ml && self.ml_ready() {
+        // compiled under the `ml` feature; the base build is signal-only).
+        let enhanced_reading = {
+            #[cfg(feature = "ml")]
+            {
+                if self.config.enable_ml && self.ml_ready() {
                     // Snapshot the buffer under the lock, then drop the guard before await.
                     let buffer_snapshot = { self.data_buffer.read().clone() };
                     self.enhance_with_ml(reading, &buffer_snapshot).await?
                 } else {
                     reading
+                }
+            }
+            #[cfg(not(feature = "ml"))]
+            {
+                reading
+            }
         };
 
         // Check minimum confidence
@@ -230,6 +250,7 @@ impl DetectionPipeline {
     }
 
     /// Enhance detection results with ML predictions
+    #[cfg(feature = "ml")]
     async fn enhance_with_ml(
         &self,
         traditional_reading: Option<VitalSignsReading>,
@@ -262,6 +283,7 @@ impl DetectionPipeline {
     }
 
     /// Get the latest ML detection results (if ML is enabled)
+    #[cfg(feature = "ml")]
     pub async fn get_ml_results(&self) -> Option<MlDetectionResult> {
         let ml = match &self.ml_pipeline {
             Some(ml) => ml,
@@ -346,6 +368,7 @@ impl DetectionPipeline {
         self.movement_classifier = MovementClassifier::new(config.movement.clone());
 
         // Update ML pipeline if configuration changed
+        #[cfg(feature = "ml")]
         if config.enable_ml != self.config.enable_ml || config.ml_config != self.config.ml_config {
             self.ml_pipeline = if config.enable_ml {
                 config.ml_config.clone().map(MlDetectionPipeline::new)
@@ -358,6 +381,7 @@ impl DetectionPipeline {
     }
 
     /// Get the ML pipeline (if enabled)
+    #[cfg(feature = "ml")]
     pub fn ml_pipeline(&self) -> Option<&MlDetectionPipeline> {
         self.ml_pipeline.as_ref()
     }

v2/crates/wifi-densepose-mat/src/lib.rs

@@ -87,6 +87,10 @@ pub mod detection;
 pub mod domain;
 pub mod integration;
 pub mod localization;
+/// ONNX-backed ML detection. Requires the `ml` feature (pulls
+/// `wifi-densepose-nn` + `ort`). The core survivor-detection/triage
+/// pipeline works without it.
+#[cfg(feature = "ml")]
 pub mod ml;
 pub mod tracking;
 
@@ -130,6 +134,7 @@ pub use integration::{
 #[cfg_attr(docsrs, doc(cfg(feature = "api")))]
 pub use api::{create_router, AppState};
 
+#[cfg(feature = "ml")]
 pub use ml::{
     AttenuationPrediction,
     BreathingClassification,
@@ -207,6 +212,7 @@ pub enum MatError {
     Io(#[from] std::io::Error),
 
     /// Machine learning error
+    #[cfg(feature = "ml")]
     #[error("ML error: {0}")]
     Ml(#[from] ml::MlError),
 }
@@ -592,8 +598,6 @@ pub mod prelude {
         AssociationResult,
         BreathingPattern,
         Coordinates3D,
-        DebrisClassification,
-        DebrisModel,
         DetectionEvent,
         DetectionObservation,
         // Detection
@@ -614,11 +618,6 @@ pub mod prelude {
         // Localization
         LocalizationService,
         MatError,
-        MaterialType,
-        // ML types
-        MlDetectionConfig,
-        MlDetectionPipeline,
-        MlDetectionResult,
         Priority,
         Result,
         ScanZone,
@@ -631,12 +630,17 @@ pub mod prelude {
         TrackerConfig,
         TrackingEvent,
         TriageStatus,
-        UncertaintyEstimate,
-        VitalSignsClassifier,
         VitalSignsDetector,
         VitalSignsReading,
         ZoneBounds,
     };
+
+    // ONNX-backed ML types — only when the `ml` feature is enabled.
+    #[cfg(feature = "ml")]
+    pub use crate::{
+        DebrisClassification, DebrisModel, MaterialType, MlDetectionConfig, MlDetectionPipeline,
+        MlDetectionResult, UncertaintyEstimate, VitalSignsClassifier,
+    };
 }
 
 #[cfg(test)]