refactor: IEffect interface

inc/IEffect.h

@@ -0,0 +1,10 @@
+#pragma once
+#include <vector>
+class IEffect {
+  private:
+    /* data */
+  public:
+    virtual void Trigger() = 0;
+    virtual void Release() = 0;
+    virtual void Process(std::vector<float>& samples) = 0;
+};