feat: stabilize Xingtu market data sync

src/shared/rate-normalizer.ts

@@ -17,6 +17,16 @@ export function normalizeRateDisplay(value: string): string {
   return trimmedValue.replace(/\s+/g, "");
 }
 
+export function normalizeFractionRateDisplay(value: string): string | null {
+  const numericValue = Number(value);
+  if (!Number.isFinite(numericValue)) {
+    return null;
+  }
+
+  const percentageValue = numericValue * 100;
+  return `${trimTrailingZeros(percentageValue.toFixed(6))}%`;
+}
+
 export function parseRateLowerBound(value: string | null | undefined): number | null {
   const comparableRate = toComparableRate(value);
   return comparableRate?.numeric ?? null;
@@ -86,3 +96,7 @@ function toComparableRate(value: string | null | undefined): ComparableRate | nu
 
   return null;
 }
+
+function trimTrailingZeros(value: string): string {
+  return value.replace(/\.?0+$/, "");
+}