fix: resolve all compiler warnings for clean build

- Remove duplicate PageRankOp/Request/Response types from centrality.rs
  (already defined in messages.rs, causing ambiguous glob re-exports)
- Remove unused serde imports from centrality.rs
- Remove unused HashMap import from paths.rs
- Replace deprecated gen_bool with random_bool in explainability.rs
- Remove unused neighbors_u variable in cycles.rs
- Fix unused edges assignment in motif.rs

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: mivertowski

crates/rustkernel-graph/src/centrality.rs

@@ -24,53 +24,13 @@ use rustkernel_core::{
     kernel::KernelMetadata,
     traits::{BatchKernel, GpuKernel, RingKernelHandler},
 };
-use serde::{Deserialize, Serialize};
 use std::collections::VecDeque;
 use std::time::Instant;
 
 // ============================================================================
 // PageRank Kernel
 // ============================================================================
 
-/// PageRank operation type.
-#[derive(Debug, Clone, Copy, Serialize, Deserialize)]
-pub enum PageRankOp {
-    /// Query the current PageRank score for a node.
-    Query,
-    /// Perform one iteration of PageRank.
-    Iterate,
-    /// Reset all scores.
-    Reset,
-    /// Initialize with a graph.
-    Initialize,
-}
-
-/// PageRank request.
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct PageRankRequest {
-    /// Node ID to query (for Query operation).
-    pub node_id: Option<u64>,
-    /// Operation type.
-    pub operation: PageRankOp,
-    /// Graph data (for Initialize operation).
-    pub graph: Option<CsrGraph>,
-    /// Damping factor (default: 0.85).
-    pub damping: Option<f32>,
-}
-
-/// PageRank response.
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct PageRankResponse {
-    /// Score for the queried node.
-    pub score: Option<f64>,
-    /// Whether the algorithm has converged.
-    pub converged: bool,
-    /// Current iteration count.
-    pub iteration: u32,
-    /// Full result (for Query after convergence).
-    pub result: Option<CentralityResult>,
-}
-
 /// PageRank kernel state.
 #[derive(Debug, Clone, Default)]
 pub struct PageRankState {

crates/rustkernel-graph/src/cycles.rs

@@ -86,8 +86,6 @@ impl ShortCycleParticipation {
 
         // For each edge, check if reciprocal exists
         for u in 0..n {
-            let neighbors_u: HashSet<u64> = graph.neighbors(u as u64).iter().copied().collect();
-
             for &v in graph.neighbors(u as u64) {
                 // Check if edge v -> u exists (reciprocal)
                 if graph.neighbors(v).contains(&(u as u64)) {

crates/rustkernel-graph/src/motif.rs

@@ -196,7 +196,6 @@ impl MotifDetection {
         let n = graph.num_nodes;
         let mut triangles = 0u64;
         let mut wedges = 0u64;
-        let mut edges = 0u64;
 
         // Count triangles and wedges
         for u in 0..n {
@@ -226,7 +225,7 @@ impl MotifDetection {
         triangles /= 3;
 
         // Edges count
-        edges = graph.num_edges as u64 / 2; // Undirected edges
+        let edges = graph.num_edges as u64 / 2; // Undirected edges
 
         let mut motif_counts = std::collections::HashMap::new();
         motif_counts.insert("triangles".to_string(), triangles);

crates/rustkernel-graph/src/paths.rs

@@ -8,7 +8,7 @@
 use crate::types::CsrGraph;
 use rustkernel_core::{domain::Domain, kernel::KernelMetadata, traits::GpuKernel};
 use std::cmp::Ordering;
-use std::collections::{BinaryHeap, HashMap, VecDeque};
+use std::collections::{BinaryHeap, VecDeque};
 
 // ============================================================================
 // Shortest Path Results

crates/rustkernel-ml/src/explainability.rs

@@ -190,7 +190,7 @@ impl SHAPValues {
 
         // Sample random coalitions
         for _ in 2..n_samples {
-            let coalition: Vec<bool> = (0..n_features).map(|_| rng.gen_bool(0.5)).collect();
+            let coalition: Vec<bool> = (0..n_features).map(|_| rng.random_bool(0.5)).collect();
 
             let z: usize = coalition.iter().filter(|&&b| b).count();
             let weight = Self::kernel_shap_weight(n_features, z);