fix: Cover transparent gap above sticky review header

Use negative margin to pull sticky header into the parent space-y-3 gap,
with matching padding and bg-background to paint over it when stuck.

apps/web/src/components/review/ReviewTab.tsx

@@ -325,7 +325,8 @@ export function ReviewTab({ initiativeId }: ReviewTabProps) {
   return (
     <div>
       {/* Header: phase selector + toolbar */}
-      <div ref={headerRef} className="sticky top-0 z-20 rounded-t-lg border border-border bg-card">
+      <div ref={headerRef} className="sticky top-0 z-20 -mt-3 pt-3 bg-background">
+      <div className="rounded-t-lg border border-border bg-card">
       <ReviewHeader
         phases={reviewablePhases.map((p) => ({ id: p.id, name: p.name, status: p.status }))}
         activePhaseId={activePhaseId}
@@ -345,6 +346,7 @@ export function ReviewTab({ initiativeId }: ReviewTabProps) {
         totalCount={allFiles.length}
       />
       </div>
+      </div>
 
       {/* Main content area — sidebar always rendered to preserve state */}
       <div className="grid grid-cols-1 lg:grid-cols-[260px_1fr] rounded-b-lg border-x border-b border-border bg-card">