style: 移除左侧导航选中态的蓝色指示条

src/renderer/src/styles/app.css

@@ -226,17 +226,6 @@ textarea:focus-visible {
   font-weight: 650;
 }
 
-.rail-item.active::before {
-  content: "";
-  position: absolute;
-  left: -8px;
-  top: 16px;
-  bottom: 16px;
-  width: 3px;
-  border-radius: 0 3px 3px 0;
-  background: var(--blue);
-}
-
 .rail-spacer {
   flex: 1;
 }