feat: add marketplace differentiation to Experiment Tracker

Each experiment now tracks which marketplace (Amazon DE, UK, etc.) it
applies to. The form defaults to the currently active marketplace filter,
and the delta % calculation filters by both product line and marketplace.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

components/WeeklyGrid.tsx

@@ -666,7 +666,7 @@ const WeeklyGrid: React.FC<WeeklyGridProps & { top50Mode: 'eu' | 'uk' }> = ({
     return (
         <div className="flex flex-col gap-3 md:gap-4 animate-fade-in px-1 md:px-0">
             {/* Experiment Tracker */}
-            <ExperimentTracker rows={rows} weeks={weeks} primaryMetric={primaryMetric} />
+            <ExperimentTracker rows={rows} weeks={weeks} primaryMetric={primaryMetric} customerFilters={customerFilters} />
 
             {/* Toolbar: Search & Pagination */}
             <div className="flex flex-col lg:flex-row justify-between items-center gap-3 md:gap-4 bg-slate-900 border border-white/10 p-2 md:p-4 rounded-xl shadow-lg">