fix(analysis): use compound inflation calculation instead of linear sum

apps/frontend/src/features/analysis/components/MonthlyVariationTable.tsx

@@ -258,14 +258,16 @@ export function MonthlyVariationTable() {
 
     const accumulatedInflation = rows.reduce<number | null>((acc, row) => {
       if (row.inflation === null) return acc;
-      return (acc ?? 0) + row.inflation;
+      const factor = 1 + row.inflation / 100;
+      return (acc ?? 1) * factor;
     }, null);
 
     return {
       BELO: totalVariation(oldest.BELO.current, newest.BELO.current),
       BLUE: totalVariation(oldest.BLUE.current, newest.BLUE.current),
       BNA: totalVariation(oldest.BNA.current, newest.BNA.current),
-      inflation: accumulatedInflation,
+      inflation:
+        accumulatedInflation !== null ? (accumulatedInflation - 1) * 100 : null,
       period: `${oldest.label} – ${newest.label}`,
     };
   }, [rows]);