refactor: rename forms

Program.cs

@@ -6,7 +6,7 @@ internal static class Program
         static void Main()
         {
             ApplicationConfiguration.Initialize();
-            Application.Run(new Form1());
+            Application.Run(new SoundBoxMain());
         }
     }
 }

Form1.cs → SoundBoxMain.cs

@@ -4,7 +4,7 @@
 
 namespace SoundBox
 {
-    public partial class Form1 : Form
+    public partial class SoundBoxMain : Form
     {
         private readonly AudioEngine _engine = new();
         private readonly List<AudioGraph> _graphs = new();
@@ -30,7 +30,7 @@ public partial class Form1 : Form
         private const int TitleBarH = 38;
         private const int ToolBarH = 40;
 
-        public Form1()
+        public SoundBoxMain()
         {
             InitializeComponent();
             BuildUI();