feat: Improve Bottle Split UX

- Add 'Split starten' button to bottle detail page
- Support flexible sample sizes (1-20cl) instead of fixed 5/10cl
- Preselect bottle when coming from bottle page
- Save sample sizes/shipping defaults to localStorage
- Update schema: sample_sizes JSONB array
- Update server actions and UI for dynamic sizes

src/components/BottleDetails.tsx

@@ -2,7 +2,7 @@
 
 import React from 'react';
 import Link from 'next/link';
-import { ChevronLeft, Calendar, Award, Droplets, MapPin, Tag, ExternalLink, Package, Info, Loader2, WifiOff, CircleDollarSign, Wine, CheckCircle2, Circle, ChevronDown, Plus } from 'lucide-react';
+import { ChevronLeft, Calendar, Award, Droplets, MapPin, Tag, ExternalLink, Package, Info, Loader2, WifiOff, CircleDollarSign, Wine, CheckCircle2, Circle, ChevronDown, Plus, Share2 } from 'lucide-react';
 import { motion, AnimatePresence } from 'framer-motion';
 import { updateBottle } from '@/services/update-bottle';
 import { getStorageUrl } from '@/lib/supabase';
@@ -248,6 +248,13 @@ export default function BottleDetails({ bottleId, sessionId, userId }: BottleDet
                         ) : (
                             <>
                                 <EditBottleForm bottle={bottle as any} />
+                                <Link
+                                    href={`/splits/create?bottle=${bottle.id}`}
+                                    className="px-5 py-3 bg-zinc-800 hover:bg-zinc-700 text-white rounded-2xl text-xs font-black uppercase tracking-widest flex items-center gap-2 transition-all border border-zinc-700 hover:border-orange-600/50"
+                                >
+                                    <Share2 size={16} className="text-orange-500" />
+                                    Split starten
+                                </Link>
                                 <DeleteBottleButton bottleId={bottle.id} />
                             </>
                         )}