Polish selected-first filter shells after simplify.

Drop redundant comments, use a Set for mobile checkmarks, and keep behavior unchanged.

src/components/campaign/shared/CampaignHeaderFilterPopover.tsx

@@ -101,8 +101,6 @@ export const CampaignHeaderFilterPopover = ({
   const filteredRows = needle
     ? searchIndex.filter((entry) => entry.haystack.includes(needle)).map((entry) => entry.row)
     : optionRows
-  // Order only while open: a closed popover keeps the natural facet order, and
-  // the snapshot is irrelevant until the next open.
   const { ordered: visibleRows, selectedCount } =
     open && isMultiSelect
       ? orderFilterOptionsSelectedFirst(filteredRows, selectionSnapshot)

src/components/campaign/shared/CampaignMobileMultiFilterField.tsx

@@ -27,6 +27,7 @@ export const CampaignMobileMultiFilterField = ({
   // No snapshot: the NativeSelect closes on every choice, so the next open
   // already wants the just-toggled value at the top.
   const { ordered } = orderFilterOptionsSelectedFirst(options, selected)
+  const selectedSet = new Set(selected)
 
   return (
     <Field>
@@ -44,7 +45,7 @@ export const CampaignMobileMultiFilterField = ({
         </NativeSelectOption>
         {ordered.map((option) => (
           <NativeSelectOption key={option.value} value={option.value}>
-            {selected.includes(option.value) ? `✓ ${option.label}` : option.label}
+            {selectedSet.has(option.value) ? `✓ ${option.label}` : option.label}
           </NativeSelectOption>
         ))}
       </NativeSelect>

tests/unit/campaignHeaderFilterPopover.unit.spec.ts

@@ -176,7 +176,6 @@ describe('CampaignHeaderFilterPopover selected-first ordering', () => {
       target: { value: 'o' },
     })
 
-    // Echo / Foxtrot / Golf / Hotel match "o"; selected (Hotel, Foxtrot) first.
     expect(labelsInOrder(optionNav())).toEqual(['Foxtrot', 'Hotel', 'Echo', 'Golf'])
   })