refactor(ecommerce): extract platform rules and prompt builders

src/features/ecommerce/utils/ratioUtils.ts

@@ -1,15 +1,19 @@
-// 比例 / 尺寸相关的纯计算工具。
-// 从 EcommercePage.tsx 抽出，逻辑零改动，仅加 export 以便单测。
+// Ratio and dimension formatting helpers.
+// Keep compatibility with a few legacy mojibake tokens, but never emit them.
 // normalizeRatioForPlatform / formatUploadedImageRatio 因依赖平台规格表与 CloneImageItem，
 // 暂留在 EcommercePage.tsx，后续随 platformSpec 一起整理。
 
+const LEGACY_MULTIPLY_SIGN = "\u8133";
+const LEGACY_FULLWIDTH_COLON = "\u951b?";
+const LEGACY_PRODUCT_IMAGE_LABEL = "\u935f\u55d7\u6427\u9365?";
+
 export const normalizeRatioToken = (value: string) =>
   value
     .replaceAll("\u00a0", " ")
-    .replaceAll("脳", "×")
+    .replaceAll(LEGACY_MULTIPLY_SIGN, "×")
     .replaceAll("*", "×")
     .replaceAll("：", ":")
-    .replace(/锛\?/g, ":")
+    .replaceAll(LEGACY_FULLWIDTH_COLON, ":")
     .replace(/\s+/g, " ")
     .trim();
 
@@ -64,7 +68,7 @@ export const formatRatioDisplayValue = (value: string) => {
     .replace("短视频", "短视频")
     .replace("主图", "主图")
     .replace("商品主图", "商品主图")
-    .replace("鍟嗗搧鍥?", "商品图")
+    .replace(LEGACY_PRODUCT_IMAGE_LABEL, "商品图")
     .replace(/\s+:/g, ":")
     .replace(/:\s+/g, ":");
 };