chore(webapp): drop server-changes note, tighten fade helper

Un-export the mask constant (only used inside the module) and fold the
truncate check into the overflow argument.

Author: samejr

.server-changes/side-menu-label-fade.md

@@ -126,7 +126,7 @@ export function EnvironmentLabel({
         environmentTextClassName(environment),
         className
       )}
-      style={truncate ? undefined : labelOverflowFadeStyle(isTruncated)}
+      style={labelOverflowFadeStyle(!truncate && isTruncated)}
     >
       {text}
     </span>

apps/webapp/app/components/environments/EnvironmentLabel.tsx

@@ -3,8 +3,7 @@
  * it only while the text actually overflows — masking a label that fits would fade its last
  * characters for no reason.
  */
-export const LABEL_OVERFLOW_MASK =
-  "linear-gradient(to right, black calc(100% - 1.5rem), transparent)";
+const LABEL_OVERFLOW_MASK = "linear-gradient(to right, black calc(100% - 1.5rem), transparent)";
 
 /** Mask style for a clipping label, or nothing when the text fits. Spread into a `style` prop. */
 export function labelOverflowFadeStyle(isOverflowing: boolean) {