Feat: polyphony + iterator reset

src/engine/sequencer.rs

@@ -450,6 +450,10 @@ impl RunsCounter {
         *count += 1;
         current
     }
+
+    fn clear_pattern(&mut self, bank: usize, pattern: usize) {
+        self.counts.retain(|&(b, p, _), _| b != bank || p != pattern);
+    }
 }
 
 pub(crate) struct TickInput {
@@ -716,6 +720,7 @@ impl SequencerState {
                         }
                     }
                 };
+                self.runs_counter.clear_pattern(pending.id.bank, pending.id.pattern);
                 self.audio_state.active_patterns.insert(
                     pending.id,
                     ActivePattern {