Fixed builders

app/MindWork AI Studio/Tools/MIME/ApplicationBuilder.cs

@@ -1,11 +1,16 @@
 namespace AIStudio.Tools.MIME;
 
-public class ApplicationBuilder : Builder, ISubtype
+public class ApplicationBuilder : ISubtype
 {
-    private ApplicationBuilder()
+    private readonly BaseType baseType;
+    
+    private ApplicationBuilder(BaseType baseType)
     {
+        this.baseType = baseType;
     }
 
+    public static ApplicationBuilder Create() => new(BaseType.APPLICATION);
+    
     private ApplicationSubtype subtype;
     
     public ApplicationBuilder UseSubtype(string subType)

app/MindWork AI Studio/Tools/MIME/AudioBuilder.cs

@@ -1,11 +1,16 @@
 namespace AIStudio.Tools.MIME;
 
-public class AudioBuilder : Builder, ISubtype
+public class AudioBuilder : ISubtype
 {
-    private AudioBuilder()
+    private readonly BaseType baseType;
+    
+    private AudioBuilder(BaseType baseType)
     {
+        this.baseType = baseType;
     }
 
+    public static AudioBuilder Create() => new(BaseType.AUDIO);
+
     private AudioSubtype subtype;
 
     public AudioBuilder UseSubtype(string subType)

app/MindWork AI Studio/Tools/MIME/Builder.cs

@@ -2,12 +2,10 @@ namespace AIStudio.Tools.MIME;
 
 public class Builder
 {
-    protected Builder()
+    private Builder()
     {
     }
     
-    protected BaseType baseType;
-    
     public static Builder Create() => new();
     
     public static MIMEType FromTextRepresentation(string textRepresentation)
@@ -48,33 +46,13 @@ public class Builder
         }
     }
     
-    public ApplicationBuilder UseApplication() 
+    public ApplicationBuilder UseApplication() => ApplicationBuilder.Create();
-    {
-        this.baseType = BaseType.APPLICATION;
-        return (ApplicationBuilder)this;
-    }
 
-    public TextBuilder UseText() 
+    public TextBuilder UseText() => TextBuilder.Create();
-    {
-        this.baseType = BaseType.TEXT;
-        return (TextBuilder)this;
-    }
 
-    public AudioBuilder UseAudio() 
+    public AudioBuilder UseAudio() => AudioBuilder.Create();
-    {
-        this.baseType = BaseType.AUDIO;
-        return (AudioBuilder)this;
-    }
 
-    public ImageBuilder UseImage() 
+    public ImageBuilder UseImage() => ImageBuilder.Create();
-    {
-        this.baseType = BaseType.IMAGE;
-        return (ImageBuilder)this;
-    }
 
-    public VideoBuilder UseVideo() 
+    public VideoBuilder UseVideo() => VideoBuilder.Create();
-    {
-        this.baseType = BaseType.VIDEO;
-        return (VideoBuilder)this;
-    }
 }

app/MindWork AI Studio/Tools/MIME/ImageBuilder.cs

@@ -1,11 +1,16 @@
 namespace AIStudio.Tools.MIME;
 
-public class ImageBuilder : Builder, ISubtype
+public class ImageBuilder : ISubtype
 {
-    private ImageBuilder()
+    private readonly BaseType baseType;
+    
+    private ImageBuilder(BaseType baseType)
     {
+        this.baseType = baseType;
     }
 
+    public static ImageBuilder Create() => new(BaseType.IMAGE);
+
     private ImageSubtype subtype;
 
     public ImageBuilder UseSubtype(string subType)

app/MindWork AI Studio/Tools/MIME/TextBuilder.cs

@@ -1,11 +1,16 @@
 namespace AIStudio.Tools.MIME;
 
-public class TextBuilder : Builder, ISubtype
+public class TextBuilder : ISubtype
 {
-    private TextBuilder()
+    private readonly BaseType baseType;
+    
+    private TextBuilder(BaseType baseType)
     {
+        this.baseType = baseType;
     }
 
+    public static TextBuilder Create() => new(BaseType.TEXT);
+    
     private TextSubtype subtype;
 
     public TextBuilder UseSubtype(string subType)

app/MindWork AI Studio/Tools/MIME/VideoBuilder.cs

@@ -1,11 +1,16 @@
 namespace AIStudio.Tools.MIME;
 
-public class VideoBuilder : Builder, ISubtype
+public class VideoBuilder : ISubtype
 {
-    private VideoBuilder()
+    private readonly BaseType baseType;
+    
+    private VideoBuilder(BaseType baseType)
     {
+        this.baseType = baseType;
     }
 
+    public static VideoBuilder Create() => new(BaseType.VIDEO);
+    
     private VideoSubtype subtype;
 
     public VideoBuilder UseSubtype(string subType)