Scope the submenu reopen guard to the browser's own light dismiss

A submenu's close() marked every close it caused as recent, so the
250ms guard meant to stop a trigger's own click reopening a popover
the same press just light-dismissed also blocked a deliberate
keyboard reopen (Enter/Space right after ArrowLeft) that happened to
land within that window. Only a close the browser made on its own
now counts toward the guard; close() marks its own hidePopover() call
explicit so it never seeds it. Fixes the "opens a submenu with Right,
Enter or Space" browser test (plan step 36, actions group).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

resources/js/menu.js

@@ -45,7 +45,9 @@ const ITEMS = '[role="menuitem"], [role="menuitemcheckbox"], [role="menuitemradi
 // A popover="auto" closes on the press that lands on its trigger, and the click that follows
 // would open it again. A close this recent is taken as that press. It is timed from
 // `beforetoggle`, which fires as the popover closes: `toggle` is queued, and arrives after that
-// click.
+// click. Only a close the browser made on its own (light dismiss) sets it — `close()` marks its
+// own as explicit, so a keyboard command that shuts a menu never guards against reopening it a
+// moment later, only the browser's own light dismiss racing the click it precedes does.
 const REOPEN_GUARD_MS = 250
 
 // A submenu opens after the pointer has rested on its item for a moment, and closes a moment after
@@ -56,6 +58,7 @@ const HOVER_CLOSE_MS = 320
 
 const menu = () => ({
     closedAt: -Infinity,
+    closingExplicitly: false,
     anchored: null,
     returnFocus: true,
     focusWasInside: false,
@@ -104,7 +107,11 @@ const menu = () => ({
             this.focusWasInside = event.newState === 'closed' && menu.contains(document.activeElement)
 
             if (event.newState === 'closed') {
-                this.closedAt = performance.now()
+                if (!this.closingExplicitly) {
+                    this.closedAt = performance.now()
+                }
+
+                this.closingExplicitly = false
             }
         })
 
@@ -336,6 +343,7 @@ const menu = () => ({
         }
 
         if (this.$refs.menu.matches(':popover-open')) {
+            this.closingExplicitly = true
             this.$refs.menu.hidePopover()
         }