docs(discovery): treat last step like noActivator for centered backdrop

Author: johnleider

apps/docs/src/components/discovery/DiscoveryContent.vue

@@ -115,9 +115,8 @@
       if (isActive) {
         isReady.value = false
 
-        // Skip polling for steps with no activator
         const step = discovery.steps.get(root.step)
-        if (step?.noActivator) {
+        if (step?.noActivator || discovery.isLast.value) {
           isReady.value = true
           return
         }

apps/docs/src/components/discovery/DiscoveryHighlight.vue

@@ -71,9 +71,8 @@
       return
     }
 
-    // Clear rect for steps with no activator (scrim still shows, just no cutout)
     const step = discovery.steps.get(id)
-    if (step?.noActivator) {
+    if (step?.noActivator || discovery.isLast.value) {
       if (rect.value !== null) rect.value = null
       return
     }