feat(partners): restore rail logo color on rail hover, not per-cell

Switch from per-cell `group-hover` to a named `group/rail` on the
PartnersRail outer container. Hovering anywhere within the rail now
restores all logos to full color and brightness in one motion, rather
than only the cell directly under the cursor.

Author: tannerlinsley

src/components/RightRail.tsx

@@ -115,7 +115,7 @@ export function PartnersRail({
   let slotIndex = 0
 
   return (
-    <div className="flex flex-col border-l border-gray-500/20 rounded-bl-lg overflow-hidden w-full">
+    <div className="group/rail flex flex-col border-l border-gray-500/20 rounded-bl-lg overflow-hidden w-full">
       <div className="w-full flex gap-2 justify-between items-center border-b border-gray-500/20 px-3 py-2">
         <Link
           className="font-medium opacity-60 hover:opacity-100 text-xs"
@@ -205,7 +205,7 @@ function PartnersRailItem({
       target="_blank"
       rel="noreferrer"
       className={twMerge(
-        'group flex items-center justify-center overflow-hidden border-r border-b border-gray-500/20 hover:bg-gray-500/10 transition-colors duration-150 ease-out',
+        'flex items-center justify-center overflow-hidden border-r border-b border-gray-500/20 hover:bg-gray-500/10 transition-colors duration-150 ease-out',
         layout.flexBasis,
         layout.minHeight,
         layout.padding,
@@ -223,7 +223,7 @@ function PartnersRailItem({
     >
       <div
         className={twMerge(
-          'w-full flex items-center justify-center mx-auto grayscale brightness-90 group-hover:grayscale-0 group-hover:brightness-100 transition-[filter] duration-150 ease-out',
+          'w-full flex items-center justify-center mx-auto grayscale brightness-90 group-hover/rail:grayscale-0 group-hover/rail:brightness-100 transition-[filter] duration-150 ease-out',
           layout.logoMaxWidth,
         )}
       >