Add playerRailInner wrapper and adjust CSS styling.

Introduced a `playerRailInner` div for better structural organization and improved styling flexibility. Adjusted CSS to manage overflow and improve visual cropping while maintaining a clean radius design.

frontend/src/AppLayout.css

@@ -88,20 +88,28 @@ body {
 /* Player rail: right of board, before notes (tight) */
 .playerRail {
   min-height: 0;
-  overflow: hidden;
   border-radius: 22px;
-
   border: 1px solid rgba(255,255,255,0.08);
   background: rgba(0,0,0,0.18);
   backdrop-filter: blur(10px);
   box-shadow: 0 16px 50px rgba(0,0,0,0.35);
-
   padding: 10px 8px;
 
   display: grid;
   grid-template-rows: auto 1fr;
   justify-items: center;
   gap: 10px;
+
+  overflow: visible; /* 🔥 wichtig */
+}
+
+.playerRailInner {
+  width: 100%;
+  height: 100%;
+  overflow: hidden;        /* hier wird wieder sauber gecropped */
+  border-radius: 18px;     /* etwas kleiner als außen */
+  display: grid;
+  justify-items: center;
 }
 
 .playerRailTitle {