Feat: script execution performance optimization

src/engine/sequencer.rs

@@ -872,6 +872,8 @@ impl SequencerState {
             }
         }
 
+        let mut trace = ExecutionTrace::default();
+
         for (_id, active) in self.audio_state.active_patterns.iter_mut() {
             let Some(pattern) = self.pattern_cache.get(active.bank, active.pattern) else {
                 continue;
@@ -937,7 +939,9 @@ impl SequencerState {
                                 mouse_down,
                             };
                             if let Some(script) = resolved_script {
-                                let mut trace = ExecutionTrace::default();
+                                trace.executed_spans.clear();
+                                trace.selected_spans.clear();
+                                trace.resolved.clear();
                                 if let Ok(cmds) = self
                                     .script_engine
                                     .evaluate_with_trace(script, &ctx, &mut trace)