feat(run): lay out the Workspace lane strip as a horizontal row above the detail panel

The lane strip was a fixed-width vertical column beside the detail panel.
Flipped it to a horizontally scrolling row on top so the detail/console
area gets the full page width below it.

client/src/pages/__tests__/__snapshots__/screens.snapshot.test.tsx.snap

@@ -5762,10 +5762,10 @@ exports[`screen snapshots > Run 1`] = `
       </button>
     </div>
     <div
-      class="flex min-h-0 flex-1 gap-4"
+      class="flex min-h-0 flex-1 flex-col gap-4"
     >
       <div
-        class="flex w-60 shrink-0 flex-col gap-2 overflow-y-auto pr-1"
+        class="flex shrink-0 flex-row gap-2 overflow-x-auto pb-1"
         data-testid="lane-strip"
       >
         <p