fix(gui): improve focus handling in AutoDevVariableList #51

The commit addresses an issue where the focus handling in the AutoDevVariableList component was not properly managed, leading to inconsistent visual feedback for selected cells. The fix ensures that the selected cells are highlighted with the appropriate border, regardless of the focus state, by conditionally setting the border based on the cell's focus and selection status.

src/main/kotlin/cc/unitmesh/devti/gui/chat/AutoDevVariableList.kt

@@ -50,20 +50,16 @@ class VariableListCellRenderer : ListCellRenderer<AutoDevVariableListItemCompone
         value.foreground = if (isSelected) jList.selectionForeground else jList.foreground
         value.isEnabled = jList.isEnabled
         value.font = jList.font
-
-        var border: Border? = null
-        if (cellHasFocus) {
+        value.border = if (cellHasFocus) {
             if (isSelected) {
-                border = UIManager.getBorder("List.focusSelectedCellHighlightBorder")
-            }
-            if (border == null) {
-                border = UIManager.getBorder("List.focusCellHighlightBorder")
+                UIManager.getBorder("List.focusSelectedCellHighlightBorder")
+            } else {
+                UIManager.getBorder("List.focusCellHighlightBorder")
             }
         } else {
-            border = this.emptyBorder
+            emptyBorder
         }
 
-        value.border = border
         return value
     }
 }