Fix clippy warnings in ringkernel-procint and ringkernel-accnet

- Use sort_by_key() with Reverse instead of sort_by() in 3 places
- Use checked_div() instead of manual division check in charts.rs

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

Author: mivertowski

crates/ringkernel-accnet/src/gui/charts.rs

@@ -671,11 +671,7 @@ impl MethodDistribution {
 
         for (i, label) in labels.iter().enumerate() {
             let x = rect.left() + 5.0 + legend_spacing * (i as f32 + 0.5);
-            let pct = if total > 0 {
-                self.counts[i] * 100 / total
-            } else {
-                0
-            };
+            let pct = (self.counts[i] * 100).checked_div(total).unwrap_or(0);
 
             painter.circle_filled(Pos2::new(x - 15.0, legend_y + 5.0), 4.0, colors[i]);
             painter.text(

crates/ringkernel-accnet/src/gui/heatmaps.rs

@@ -151,7 +151,7 @@ impl ActivityHeatmap {
     pub fn from_network_top_accounts(network: &AccountingNetwork, top_n: usize) -> Self {
         // Get top N accounts by transaction count
         let mut accounts: Vec<_> = network.accounts.iter().enumerate().collect();
-        accounts.sort_by(|a, b| b.1.transaction_count.cmp(&a.1.transaction_count));
+        accounts.sort_by_key(|a| std::cmp::Reverse(a.1.transaction_count));
         accounts.truncate(top_n);
 
         let mut data = vec![vec![0.0f32; 8]; accounts.len()];

crates/ringkernel-procint/src/analytics/pattern_analysis.rs

@@ -76,7 +76,7 @@ impl PatternAggregator {
     /// Get top patterns by frequency.
     pub fn top_patterns(&self, n: usize) -> Vec<&PatternSummary> {
         let mut sorted: Vec<_> = self.recent_patterns.iter().collect();
-        sorted.sort_by(|a, b| b.frequency.cmp(&a.frequency));
+        sorted.sort_by_key(|a| std::cmp::Reverse(a.frequency));
         sorted.truncate(n);
         sorted
     }

crates/ringkernel-procint/src/gui/app.rs

@@ -384,7 +384,7 @@ impl ProcessIntelligenceApp {
 
         // Get variations sorted by count
         let mut variations: Vec<_> = self.coordinator.variations().values().collect();
-        variations.sort_by(|a, b| b.count.cmp(&a.count));
+        variations.sort_by_key(|a| std::cmp::Reverse(a.count));
 
         // Get activity names and colors
         let sector = self.coordinator.pipeline().sector();