Position SpringBoard UI on right side like original Chili layout

Changed body#springboard to match TabbedWindow layout:
- Position: absolute, right: 0dp (anchored to right side)
- Width: 500dp (matches SB.conf.RIGHT_PANEL_WIDTH)
- This leaves the left side of the screen open for the game view,
  matching the original Chili UI layout

Author: claude

scen_edit/view/rcss/springboard.rcss

@@ -2,7 +2,10 @@ body#springboard {
     font-family: Poppins;
     font-size: 14dp;
     color: #cccccc;
-    width: 100%;
+    position: absolute;
+    right: 0dp;
+    top: 0dp;
+    width: 500dp;
     height: 100%;
     background-color: #1a1a1a;
 }