Add dynamic keyboard dimensions and integrate adjustable knob

Introduced adjustable `keyboardWidth` and `keyboardHeight` for `KeyboardComponent`, making dimensions dynamic. Added a knob component to control keyboard width in `MainView`. Enhanced layouts for flexibility and customization.

test-app/src/jsMain/kotlin/nl/astraeus/vst/ui/view/MainView.kt

@@ -4,10 +4,12 @@ package nl.astraeus.vst.ui.view
 
 import kotlinx.html.div
 import kotlinx.html.h1
+import kotlinx.html.hr
 import kotlinx.html.js.onClickFunction
 import kotlinx.html.option
 import kotlinx.html.select
 import kotlinx.html.span
+import kotlinx.html.style
 import nl.astraeus.css.properties.AlignItems
 import nl.astraeus.css.properties.BoxSizing
 import nl.astraeus.css.properties.Display
@@ -39,6 +41,7 @@ import nl.astraeus.vst.ui.css.hover
 class MainView : Komponent() {
   private var messages: MutableList<String> = ArrayList()
   var started = true
+  var keyboardWidth = 500
 
   fun addMessage(message: String) {
     messages.add(message)
@@ -113,7 +116,30 @@ class MainView : Komponent() {
         }
       }
       div {
-        include(KeyboardComponent())
+        style = "height: 150px;"
+        include(
+          KnobComponent(
+            value = keyboardWidth.toDouble(),
+            label = "Keyboard",
+            minValue = 100.0,
+            maxValue = 2000.0,
+            step = 5.0,
+            width = 100,
+            height = 120,
+          ) { value ->
+            keyboardWidth = value.toInt()
+            requestUpdate()
+          }
+        )
+      }
+      hr {}
+      div {
+        include(KeyboardComponent(
+          keyboardWidth = keyboardWidth,
+          keyboardHeight = keyboardWidth / 2,
+          onNoteDown = { println("Note down: $it") },
+          onNoteUp = { println("Note up: $it") },
+        ))
       }
         /*
       div {