feat(ruvector): implement ADR-017 as wifi-densepose-ruvector crate + fix MAT warnings

New crate `wifi-densepose-ruvector` implements all 7 ruvector v2.0.4
integration points from ADR-017 (signal processing + MAT disaster detection):

signal::subcarrier   — mincut_subcarrier_partition (ruvector-mincut)
signal::spectrogram  — gate_spectrogram (ruvector-attn-mincut)
signal::bvp          — attention_weighted_bvp (ruvector-attention)
signal::fresnel      — solve_fresnel_geometry (ruvector-solver)
mat::triangulation   — solve_triangulation TDoA (ruvector-solver)
mat::breathing       — CompressedBreathingBuffer 50-75% mem reduction (ruvector-temporal-tensor)
mat::heartbeat       — CompressedHeartbeatSpectrogram tiered compression (ruvector-temporal-tensor)

16 tests, 0 compilation errors. Workspace grows from 14 → 15 crates.

MAT crate: fix all 54 warnings (0 remaining in wifi-densepose-mat):
- Remove unused imports (Arc, HashMap, RwLock, mpsc, Mutex, ConfidenceScore, etc.)
- Prefix unused variables with _ (timestamp_low, agc, perm)
- Add #![allow(unexpected_cfgs)] for onnx feature gates in ML files
- Move onnx-conditional imports under #[cfg(feature = "onnx")] guards

README: update crate count 14→15, ADR count 24→26, add ruvector crate
table with 7-row integration summary.

Total tests: 939 → 955 (16 new). All passing, 0 regressions.

https://claude.ai/code/session_0164UZu6rG6gA15HmVyLZAmU

rust-port/wifi-densepose-rs/crates/wifi-densepose-ruvector/src/signal/subcarrier.rs

@@ -0,0 +1,178 @@
+//! Subcarrier partitioning via graph min-cut (ruvector-mincut).
+//!
+//! Uses [`MinCutBuilder`] to partition subcarriers into two groups —
+//! **sensitive** (high body-motion correlation) and **insensitive** (dominated
+//! by static multipath or noise) — based on pairwise sensitivity similarity.
+//!
+//! The edge weight between subcarriers `i` and `j` is the inverse absolute
+//! difference of their sensitivity scores; highly similar subcarriers have a
+//! heavy edge, making the min-cut prefer to separate dissimilar ones.
+//!
+//! A virtual source (node `n`) and sink (node `n+1`) are added to make the
+//! graph connected and enable the min-cut to naturally bifurcate the
+//! subcarrier set. The cut edges that cross from the source-side to the
+//! sink-side identify the two partitions.
+
+use ruvector_mincut::{DynamicMinCut, MinCutBuilder};
+
+/// Partition `sensitivity` scores into (sensitive_indices, insensitive_indices)
+/// using graph min-cut. The group with higher mean sensitivity is "sensitive".
+///
+/// # Arguments
+///
+/// - `sensitivity`: per-subcarrier sensitivity score, one value per subcarrier.
+///   Higher values indicate stronger body-motion correlation.
+///
+/// # Returns
+///
+/// A tuple `(sensitive, insensitive)` where each element is a `Vec<usize>` of
+/// subcarrier indices belonging to that partition. Together they cover all
+/// indices `0..sensitivity.len()`.
+///
+/// # Notes
+///
+/// When `sensitivity` is empty or all edges would be below threshold the
+/// function falls back to a simple midpoint split.
+pub fn mincut_subcarrier_partition(sensitivity: &[f32]) -> (Vec<usize>, Vec<usize>) {
+    let n = sensitivity.len();
+    if n == 0 {
+        return (Vec::new(), Vec::new());
+    }
+    if n == 1 {
+        return (vec![0], Vec::new());
+    }
+
+    // Build edges as a flow network:
+    // - Nodes 0..n-1 are subcarrier nodes
+    // - Node n is the virtual source (connected to high-sensitivity nodes)
+    // - Node n+1 is the virtual sink (connected to low-sensitivity nodes)
+    let source = n as u64;
+    let sink = (n + 1) as u64;
+
+    let mean_sens: f32 = sensitivity.iter().sum::<f32>() / n as f32;
+
+    let mut edges: Vec<(u64, u64, f64)> = Vec::new();
+
+    // Source connects to subcarriers with above-average sensitivity.
+    // Sink connects to subcarriers with below-average sensitivity.
+    for i in 0..n {
+        let cap = (sensitivity[i] as f64).abs() + 1e-6;
+        if sensitivity[i] >= mean_sens {
+            edges.push((source, i as u64, cap));
+        } else {
+            edges.push((i as u64, sink, cap));
+        }
+    }
+
+    // Subcarrier-to-subcarrier edges weighted by inverse sensitivity difference.
+    let threshold = 0.1_f64;
+    for i in 0..n {
+        for j in (i + 1)..n {
+            let diff = (sensitivity[i] - sensitivity[j]).abs() as f64;
+            let weight = if diff > 1e-9 { 1.0 / diff } else { 1e6_f64 };
+            if weight > threshold {
+                edges.push((i as u64, j as u64, weight));
+                edges.push((j as u64, i as u64, weight));
+            }
+        }
+    }
+
+    let mc: DynamicMinCut = match MinCutBuilder::new().exact().with_edges(edges).build() {
+        Ok(mc) => mc,
+        Err(_) => {
+            // Fallback: midpoint split on builder error.
+            let mid = n / 2;
+            return ((0..mid).collect(), (mid..n).collect());
+        }
+    };
+
+    // Use cut_edges to identify which side each node belongs to.
+    // Nodes reachable from source in the residual graph are "source-side",
+    // the rest are "sink-side".
+    let cut = mc.cut_edges();
+
+    // Collect nodes that appear on the source side of a cut edge (u nodes).
+    let mut source_side: std::collections::HashSet<u64> = std::collections::HashSet::new();
+    let mut sink_side: std::collections::HashSet<u64> = std::collections::HashSet::new();
+
+    for edge in &cut {
+        // Cut edge goes from source-side node to sink-side node.
+        if edge.source != source && edge.source != sink {
+            source_side.insert(edge.source);
+        }
+        if edge.target != source && edge.target != sink {
+            sink_side.insert(edge.target);
+        }
+    }
+
+    // Any subcarrier not explicitly classified goes to whichever side is smaller.
+    let mut side_a: Vec<usize> = source_side.iter().map(|&x| x as usize).collect();
+    let mut side_b: Vec<usize> = sink_side.iter().map(|&x| x as usize).collect();
+
+    // Assign unclassified nodes.
+    for i in 0..n {
+        if !source_side.contains(&(i as u64)) && !sink_side.contains(&(i as u64)) {
+            if side_a.len() <= side_b.len() {
+                side_a.push(i);
+            } else {
+                side_b.push(i);
+            }
+        }
+    }
+
+    // If one side is empty (no cut edges), fall back to midpoint split.
+    if side_a.is_empty() || side_b.is_empty() {
+        let mid = n / 2;
+        side_a = (0..mid).collect();
+        side_b = (mid..n).collect();
+    }
+
+    // The group with higher mean sensitivity becomes the "sensitive" group.
+    let mean_of = |indices: &[usize]| -> f32 {
+        if indices.is_empty() {
+            return 0.0;
+        }
+        indices.iter().map(|&i| sensitivity[i]).sum::<f32>() / indices.len() as f32
+    };
+
+    if mean_of(&side_a) >= mean_of(&side_b) {
+        (side_a, side_b)
+    } else {
+        (side_b, side_a)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn partition_covers_all_indices() {
+        let sensitivity: Vec<f32> = (0..10).map(|i| i as f32 * 0.1).collect();
+        let (sensitive, insensitive) = mincut_subcarrier_partition(&sensitivity);
+
+        // Both groups must be non-empty for a non-trivial input.
+        assert!(!sensitive.is_empty(), "sensitive group must not be empty");
+        assert!(!insensitive.is_empty(), "insensitive group must not be empty");
+
+        // Together they must cover every index exactly once.
+        let mut all_indices: Vec<usize> = sensitive.iter().chain(insensitive.iter()).cloned().collect();
+        all_indices.sort_unstable();
+        let expected: Vec<usize> = (0..10).collect();
+        assert_eq!(all_indices, expected, "partition must cover all 10 indices");
+    }
+
+    #[test]
+    fn partition_empty_input() {
+        let (s, i) = mincut_subcarrier_partition(&[]);
+        assert!(s.is_empty());
+        assert!(i.is_empty());
+    }
+
+    #[test]
+    fn partition_single_element() {
+        let (s, i) = mincut_subcarrier_partition(&[0.5]);
+        assert_eq!(s, vec![0]);
+        assert!(i.is_empty());
+    }
+}