fix: restore map share toggle and fix public journey horizontal scroll

Re-adds the share_map permission toggle to the journey share settings UI so
owners can control whether the map is visible on the public share page.
Fixes horizontal scrollbar on the public journey page caused by decorative
hero circles with negative offsets overflowing the viewport.

client/src/pages/JourneyDetailPage.tsx

@@ -2941,6 +2941,7 @@ function JourneyShareSection({ journeyId }: { journeyId: number }) {
             {[
               { key: 'share_timeline' as const, label: t('journey.share.timeline'), icon: List },
               { key: 'share_gallery' as const, label: t('journey.share.gallery'), icon: Grid },
+              { key: 'share_map' as const, label: t('journey.share.map'), icon: MapPin },
             ].map(({ key, label, icon: Icon }) => (
               <button
                 key={key}

client/src/pages/JourneyPublicPage.tsx

@@ -448,7 +448,7 @@ export default function JourneyPublicPage() {
   return (
     <div className="min-h-screen bg-zinc-50 dark:bg-zinc-950">
       {/* Hero */}
-      <div className="relative text-center text-white" style={{ background: 'linear-gradient(135deg, #000 0%, #0f172a 50%, #1e293b 100%)', padding: '32px 20px 28px' }}>
+      <div className="relative text-center text-white" style={{ background: 'linear-gradient(135deg, #000 0%, #0f172a 50%, #1e293b 100%)', padding: '32px 20px 28px', overflow: 'hidden' }}>
         {journey.cover_image && (
           <div style={{ position: 'absolute', inset: 0, backgroundImage: `url(/uploads/${journey.cover_image})`, backgroundSize: 'cover', backgroundPosition: 'center', opacity: 0.15 }} />
         )}