style(lists): apply gradient PageHeader to client/interest/yacht/company/berth lists

Pulls the polished gradient hero strip into the five primary list
surfaces. PR10b-e (detail polish, dashboard/admin polish, email +
notifications polish, mobile responsive sweep) deferred to a follow-up
release per spec risk register since visual baseline regen needs hands-
on iteration.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/interests/interest-list.tsx

@@ -61,8 +61,7 @@ export function InterestList() {
   });
 
   const archiveMutation = useMutation({
-    mutationFn: (id: string) =>
-      apiFetch(`/api/v1/interests/${id}`, { method: 'DELETE' }),
+    mutationFn: (id: string) => apiFetch(`/api/v1/interests/${id}`, { method: 'DELETE' }),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ['interests'] });
       setArchiveInterest(null);
@@ -80,6 +79,7 @@ export function InterestList() {
       <PageHeader
         title="Interests"
         description="Track prospective berth interest and pipeline"
+        variant="gradient"
         actions={
           <div className="flex items-center gap-2">
             <div className="flex items-center border rounded-md overflow-hidden">
@@ -155,10 +155,7 @@ export function InterestList() {
         />
       )}
 
-      <InterestForm
-        open={createOpen}
-        onOpenChange={setCreateOpen}
-      />
+      <InterestForm open={createOpen} onOpenChange={setCreateOpen} />
 
       {editInterest && (
         <InterestForm
@@ -174,9 +171,7 @@ export function InterestList() {
         entityName={archiveInterest?.clientName ?? 'Interest'}
         entityType="Interest"
         isArchived={false}
-        onConfirm={() =>
-          archiveInterest && archiveMutation.mutate(archiveInterest.id)
-        }
+        onConfirm={() => archiveInterest && archiveMutation.mutate(archiveInterest.id)}
         isLoading={archiveMutation.isPending}
       />
     </div>