Hide menu submenus when none of their children are visible

Static submenus and links now inherit visibility from their descendants,
so hardware sections like Touchpad Haptics disappear on machines without
the hardware instead of opening empty. Laptop Display and Mirror Display
are guarded by omarchy-hw-laptop.

The guard evaluator brace-wraps every when/checked condition before
silencing it, so conditions in the jsonc no longer need their own
>/dev/null plumbing, and parents no longer need to repeat their
children's guards.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

shell/plugins/menu/MenuModel.js

@@ -173,6 +173,25 @@ function childCount(items, itemOrder, id) {
   return count
 }
 
+function isVisible(items, itemOrder, whenResults, entry, depth) {
+  if (!entry) return false
+  if (entry.when && whenResults && whenResults[entry.id] === false) return false
+  if (entry.kind !== "menu" && entry.kind !== "link") return true
+  if (entry.provider) return true
+
+  var guard = depth || 0
+  if (guard >= 32) return false
+
+  var target = entry.kind === "link" ? entry.target : entry.id
+  var order = Array.isArray(itemOrder) ? itemOrder : []
+  for (var i = 0; i < order.length; i++) {
+    var child = item(items, order[i])
+    if (child && child.parent === target && isVisible(items, itemOrder, whenResults, child, guard + 1)) return true
+  }
+
+  return false
+}
+
 function labelFor(entry, checkedResults) {
   if (!entry) return ""
   if (entry.checked && checkedResults && checkedResults[entry.id]) return entry.label + " ✓"
@@ -282,6 +301,7 @@ if (typeof module !== "undefined") {
     parentPathFor: parentPathFor,
     isDescendantOf: isDescendantOf,
     childCount: childCount,
+    isVisible: isVisible,
     labelFor: labelFor,
     searchableToken: searchableToken,
     leafIdFor: leafIdFor,