feat: show both current and previous values in Ads comparison view

- AdsPerformance.tsx: Update SummaryCard and TableCell to display 'Prev: [Value]' explicitly
- AdsPerformance.tsx: Standardized formatting using de-DE locale across all comparison metrics
- AdsPerformance.tsx: Improved growth calculation reliability in comparison mode

components/AdsPerformance.tsx

@@ -183,19 +183,19 @@ const AdsPerformance: React.FC<AdsPerformanceProps> = ({ data, filters }) => {
 
             {/* Summary Grid */}
             <div className="grid grid-cols-2 md:grid-cols-4 lg:grid-cols-7 xl:grid-cols-13 gap-4 bg-[#141820] p-4 rounded-xl border border-white/5 shadow-xl">
-                <SummaryCard label="TOTAL SALES" value={formatCurrency(totals.curr.salesTotal)} prevValue={totals.prev?.salesTotal} color="text-emerald-400" />
-                <SummaryCard label="ADS SALES" value={formatCurrency(totals.curr.salesAds)} prevValue={totals.prev?.salesAds} color="text-orange-400" />
-                <SummaryCard label="ORGANIC SALES" value={formatCurrency(totals.curr.salesOrganic)} prevValue={totals.prev?.salesOrganic} color="text-blue-400" />
-                <SummaryCard label="AD SPEND" value={formatCurrency(totals.curr.cost)} prevValue={totals.prev?.cost} color="text-indigo-400" />
-                <SummaryCard label="IMPR." value={formatNumber(totals.curr.impressions)} prevValue={totals.prev?.impressions} />
-                <SummaryCard label="CLICKS" value={formatNumber(totals.curr.clicks)} prevValue={totals.prev?.clicks} />
-                <SummaryCard label="ADS ORDERS" value={formatNumber(totals.curr.conversions)} prevValue={totals.prev?.conversions} />
-                <SummaryCard label="CPC" value={`$${currMetrics.cpc.toLocaleString('de-DE', { minimumFractionDigits: 2, maximumFractionDigits: 2 })}`} prevValue={prevMetrics?.cpc} inverse />
-                <SummaryCard label="CTR" value={formatPercent(currMetrics.ctr)} prevValue={prevMetrics?.ctr} />
-                <SummaryCard label="CVR" value={formatPercent(currMetrics.cvr)} prevValue={prevMetrics?.cvr} />
-                <SummaryCard label="ACOS" value={formatPercent(currMetrics.acos)} prevValue={prevMetrics?.acos} inverse />
-                <SummaryCard label="ROAS" value={currMetrics.roas.toFixed(2)} prevValue={prevMetrics?.roas} color="text-blue-300" />
-                <SummaryCard label="TACOS" value={formatPercent(currMetrics.tacos)} prevValue={prevMetrics?.tacos} inverse />
+                <SummaryCard label="TOTAL SALES" value={totals.curr.salesTotal} prevValue={totals.prev?.salesTotal} format="currency" color="text-emerald-400" />
+                <SummaryCard label="ADS SALES" value={totals.curr.salesAds} prevValue={totals.prev?.salesAds} format="currency" color="text-orange-400" />
+                <SummaryCard label="ORGANIC SALES" value={totals.curr.salesOrganic} prevValue={totals.prev?.salesOrganic} format="currency" color="text-blue-400" />
+                <SummaryCard label="AD SPEND" value={totals.curr.cost} prevValue={totals.prev?.cost} format="currency" color="text-indigo-400" />
+                <SummaryCard label="IMPR." value={totals.curr.impressions} prevValue={totals.prev?.impressions} format="number" />
+                <SummaryCard label="CLICKS" value={totals.curr.clicks} prevValue={totals.prev?.clicks} format="number" />
+                <SummaryCard label="ADS ORDERS" value={totals.curr.conversions} prevValue={totals.prev?.conversions} format="number" />
+                <SummaryCard label="CPC" value={currMetrics.cpc} prevValue={prevMetrics?.cpc} format="number" prefix="$" decimals={2} inverse />
+                <SummaryCard label="CTR" value={currMetrics.ctr} prevValue={prevMetrics?.ctr} format="percent" />
+                <SummaryCard label="CVR" value={currMetrics.cvr} prevValue={prevMetrics?.cvr} format="percent" />
+                <SummaryCard label="ACOS" value={currMetrics.acos} prevValue={prevMetrics?.acos} format="percent" inverse />
+                <SummaryCard label="ROAS" value={currMetrics.roas} prevValue={prevMetrics?.roas} format="number" decimals={2} color="text-blue-300" />
+                <SummaryCard label="TACOS" value={currMetrics.tacos} prevValue={prevMetrics?.tacos} format="percent" inverse />
             </div>
 
             {/* Table Section */}
@@ -271,22 +271,49 @@ const AdsPerformance: React.FC<AdsPerformanceProps> = ({ data, filters }) => {
     );
 };
 
-const SummaryCard = ({ label, value, prevValue, color = "text-white", inverse = false }: { label: string; value: string; prevValue?: number; color?: string; inverse?: boolean }) => {
-    // Correctly parse value regardless of locale formatting (handles dots as thousands and commas as decimals)
-    const numericValue = parseFloat(value.replace(/[^\d,]/g, '').replace(',', '.'));
+const SummaryCard = ({
+    label,
+    value,
+    prevValue,
+    format,
+    prefix = "",
+    decimals = 0,
+    color = "text-white",
+    inverse = false
+}: {
+    label: string;
+    value: number;
+    prevValue?: number;
+    format: 'currency' | 'number' | 'percent';
+    prefix?: string;
+    decimals?: number;
+    color?: string;
+    inverse?: boolean
+}) => {
     const growth = prevValue !== undefined && prevValue > 0
-        ? ((numericValue - prevValue) / prevValue) * 100
+        ? ((value - prevValue) / prevValue) * 100
         : null;
 
+    const formatVal = (v: number) => {
+        if (format === 'currency') return `$${Math.round(v).toLocaleString('de-DE')}`;
+        if (format === 'percent') return v.toLocaleString('de-DE', { minimumFractionDigits: 2, maximumFractionDigits: 2 }) + "%";
+        return prefix + v.toLocaleString('de-DE', { minimumFractionDigits: decimals, maximumFractionDigits: decimals });
+    };
+
     return (
         <div className="flex flex-col items-center justify-center p-2 border-r last:border-r-0 border-white/5 w-full min-w-[80px]">
             <span className={`${color} text-[10px] font-black tracking-widest mb-1 text-center leading-tight uppercase`}>{label}</span>
             <div className="flex flex-col items-center">
-                <span className="text-sm font-bold text-white transition-all">{value}</span>
-                {growth !== null && (
-                    <span className={`text-[9px] font-bold mt-0.5 ${(growth > 0 ? !inverse : inverse) ? 'text-emerald-400' : 'text-rose-500'}`}>
-                        {growth > 0 ? '↑' : '↓'} {Math.abs(growth).toFixed(1)}%
-                    </span>
+                <span className="text-sm font-bold text-white transition-all">{formatVal(value)}</span>
+                {prevValue !== undefined && (
+                    <div className="flex flex-col items-center mt-0.5">
+                        <span className="text-[9px] text-slate-500 font-medium">Prev: {formatVal(prevValue)}</span>
+                        {growth !== null && (
+                            <span className={`text-[9px] font-black ${(growth > 0 ? !inverse : inverse) ? 'text-emerald-400' : 'text-rose-500'}`}>
+                                {growth > 0 ? '↑' : '↓'} {Math.abs(growth).toFixed(1)}%
+                            </span>
+                        )}
+                    </div>
                 )}
             </div>
         </div>
@@ -296,25 +323,31 @@ const SummaryCard = ({ label, value, prevValue, color = "text-white", inverse =
 const TableCell = ({ value, prevValue, format, prefix = "", inverse = false, highlight = false }: { value: number; prevValue?: number; format: 'currency' | 'number' | 'percent'; prefix?: string; inverse?: boolean; highlight?: boolean }) => {
     const growth = prevValue !== undefined && prevValue > 0 ? ((value - prevValue) / prevValue) * 100 : null;
 
-    let displayValue = "";
-    if (format === 'currency') displayValue = Math.round(value).toLocaleString('de-DE');
-    else if (format === 'number') {
-        if (prefix === "$") {
-            displayValue = "$" + value.toLocaleString('de-DE', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
-        } else {
-            displayValue = prefix + Math.round(value).toLocaleString('de-DE');
+    const formatVal = (v: number) => {
+        if (format === 'currency') return Math.round(v).toLocaleString('de-DE');
+        if (format === 'number') {
+            if (prefix === "$") {
+                return "$" + v.toLocaleString('de-DE', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
+            } else {
+                return prefix + Math.round(v).toLocaleString('de-DE');
+            }
         }
-    }
-    else if (format === 'percent') displayValue = value.toLocaleString('de-DE', { minimumFractionDigits: 2, maximumFractionDigits: 2 }) + "%";
+        return v.toLocaleString('de-DE', { minimumFractionDigits: 2, maximumFractionDigits: 2 }) + "%";
+    };
 
     return (
         <td className="p-4 text-right">
             <div className="flex flex-col items-end">
-                <span className={`font-bold ${highlight ? 'text-blue-300' : 'text-white'}`}>{displayValue}</span>
-                {growth !== null && (
-                    <span className={`text-[9px] font-medium ${(growth > 0 ? !inverse : inverse) ? 'text-emerald-400' : 'text-rose-400'} opacity-80`}>
-                        {growth > 0 ? '+' : ''}{growth.toFixed(1)}%
-                    </span>
+                <span className={`font-bold ${highlight ? 'text-blue-300' : 'text-white'}`}>{formatVal(value)}</span>
+                {prevValue !== undefined && (
+                    <div className="flex flex-col items-end scale-[0.85] origin-right opacity-80 mt-0.5">
+                        <span className="text-[10px] text-slate-500 font-medium">Prev: {formatVal(prevValue)}</span>
+                        {growth !== null && (
+                            <span className={`text-[10px] font-black ${(growth > 0 ? !inverse : inverse) ? 'text-emerald-400' : 'text-rose-400'}`}>
+                                {growth > 0 ? '+' : ''}{growth.toFixed(1)}%
+                            </span>
+                        )}
+                    </div>
                 )}
             </div>
         </td>