fix(adr-017): Add missing cfg(feature = "ruvector") gates to MAT re-exports

Three pub use statements in detection/mod.rs and localization/mod.rs were
re-exporting ruvector-gated symbols unconditionally, and triangulation.rs
had ruvector_solver imports without feature gates. These caused unresolved-
import errors in --no-default-features builds.

- detection/mod.rs: gate CompressedBreathingBuffer + CompressedHeartbeatSpectrogram
- localization/mod.rs: gate solve_tdoa_triangulation
- triangulation.rs: gate use ruvector_solver::*, fn + test module with #[cfg]

All 7 ADR-017 integrations now compile with both default and no-default-features.

https://claude.ai/code/session_01BSBAQJ34SLkiJy4A8SoiL4

rust-port/wifi-densepose-rs/crates/wifi-densepose-mat/src/detection/mod.rs

@@ -12,8 +12,12 @@ mod heartbeat;
 mod movement;
 mod pipeline;
 
-pub use breathing::{BreathingDetector, BreathingDetectorConfig, CompressedBreathingBuffer};
+pub use breathing::{BreathingDetector, BreathingDetectorConfig};
+#[cfg(feature = "ruvector")]
+pub use breathing::CompressedBreathingBuffer;
 pub use ensemble::{EnsembleClassifier, EnsembleConfig, EnsembleResult, SignalConfidences};
-pub use heartbeat::{HeartbeatDetector, HeartbeatDetectorConfig, CompressedHeartbeatSpectrogram};
+pub use heartbeat::{HeartbeatDetector, HeartbeatDetectorConfig};
+#[cfg(feature = "ruvector")]
+pub use heartbeat::CompressedHeartbeatSpectrogram;
 pub use movement::{MovementClassifier, MovementClassifierConfig};
 pub use pipeline::{DetectionPipeline, DetectionConfig, VitalSignsDetector, CsiDataBuffer};

rust-port/wifi-densepose-rs/crates/wifi-densepose-mat/src/localization/mod.rs

@@ -9,6 +9,8 @@ mod triangulation;
 mod depth;
 mod fusion;
 
-pub use triangulation::{Triangulator, TriangulationConfig, solve_tdoa_triangulation};
+pub use triangulation::{Triangulator, TriangulationConfig};
+#[cfg(feature = "ruvector")]
+pub use triangulation::solve_tdoa_triangulation;
 pub use depth::{DepthEstimator, DepthEstimatorConfig};
 pub use fusion::{PositionFuser, LocalizationService};

rust-port/wifi-densepose-rs/crates/wifi-densepose-mat/src/localization/triangulation.rs

@@ -380,7 +380,9 @@ mod tests {
 // Integration 5: Multi-AP TDoA triangulation via NeumannSolver
 // ---------------------------------------------------------------------------
 
+#[cfg(feature = "ruvector")]
 use ruvector_solver::neumann::NeumannSolver;
+#[cfg(feature = "ruvector")]
 use ruvector_solver::types::CsrMatrix;
 
 /// Solve multi-AP TDoA survivor localization using NeumannSolver.
@@ -396,6 +398,7 @@ use ruvector_solver::types::CsrMatrix;
 ///
 /// # Returns
 /// Some((x, y)) estimated survivor position in metres, or None if underdetermined
+#[cfg(feature = "ruvector")]
 pub fn solve_tdoa_triangulation(
     tdoa_measurements: &[(usize, usize, f32)],
     ap_positions: &[(f32, f32)],
@@ -466,7 +469,7 @@ pub fn solve_tdoa_triangulation(
     Some((x_sol + x_ref, y_sol + y_ref))
 }
 
-#[cfg(test)]
+#[cfg(all(test, feature = "ruvector"))]
 mod triangulation_tests {
     use super::*;