Restore ForecastView UI, Fix default YTD logic, and Refine Seasonality (Specific > Global fallback)

services/dataProcessor.ts

@@ -1628,7 +1628,6 @@ export const calculateForecastViewData = (
     const getWeights = (records: SalesRecord[]): number[] | null => {
         const weights = new Array(12).fill(0);
         let total = 0;
-        const seenMonths = new Set<string>();
 
         records.forEach(r => {
             const m = r.month.split('-')[0];
@@ -1636,18 +1635,13 @@ export const calculateForecastViewData = (
             if (idx !== -1) {
                 weights[idx] += r.units;
                 total += r.units;
-                if (r.units > 0) seenMonths.add(m);
             }
         });
 
-        // 1. No data -> Fallback
+        // If ASIN has any 2025 sales, we trust its specific seasonality.
+        // Return null ONLY if there's no data at all for this ASIN in 2025.
         if (total === 0) return null;
 
-        // 2. Sparse Data Check (< 4 months)
-        // If an ASIN has very little history (e.g. only Jan), using its own curve implies 100% seasonality in Jan.
-        // The user requested to use the "General Catalog Seasonality" in these cases.
-        if (seenMonths.size < 4) return null;
-
         return weights.map(w => w / total);
     };