feat(douyu): 兑换成功后自动刷新积分 & 修复兑换图片首开裂图

- 兑换成功后自动调用积分查询，更新账号最新积分并写入任务结果
- 兑换图片并发生成竞态修复：同任务共享 in-flight Promise，避免 revoke 导致裂图
- 兑换图片移除积分展示

web/frontend/src/utils/exchangeImage.ts

@@ -21,7 +21,6 @@ function rawString(raw: Record<string, unknown> | null | undefined, key: string)
 function goodsOf(task: DouyuTaskItem): {
   name: string;
   pic: string;
-  points: number | null;
   roleName: string;
   channel: string;
   accountName: string;
@@ -32,13 +31,11 @@ function goodsOf(task: DouyuTaskItem): {
     || task.message.replace(/^兑换[^:：]*[:：]?\s*/, '').trim()
     || rawString(task.result, 'commodity_id');
   const pic = rawString(goods, 'webPic') || rawString(goods, 'pic');
-  const pointsValue = task.result?.esports_points_after_exchange;
-  const points = typeof pointsValue === 'number' && Number.isFinite(pointsValue) ? pointsValue : null;
   const roleName = rawString(task.result, 'game_name');
   const channel = rawString(task.result, 'game_channel');
   const accountName = rawString(task.result, 'account_name')
     || task.account_nickname || task.account_username || task.account_uid || `#${task.account_id}`;
-  return { name, pic, points, roleName, channel, accountName };
+  return { name, pic, roleName, channel, accountName };
 }
 
 function loadImage(url: string, timeoutMs = 8000): Promise<HTMLImageElement> {
@@ -172,7 +169,6 @@ export async function drawExchangeImage(task: DouyuTaskItem): Promise<Blob> {
   if (info.roleName) infoRows.push(['游戏角色', info.roleName]);
   if (info.channel) infoRows.push(['游戏区服', info.channel]);
   infoRows.push(['兑换账号', info.accountName]);
-  if (info.points != null) infoRows.push(['当前积分', `${info.points}`]);
   if (time) infoRows.push(['兑换时间', time]);
 
   ctx.font = `15px ${FONT_FAMILY}`;
@@ -220,16 +216,27 @@ interface CachedImage {
 }
 
 const imageCache = new Map<number, CachedImage>();
+const inflightImages = new Map<number, Promise<CachedImage>>();
 
 export async function getExchangeImage(task: DouyuTaskItem): Promise<CachedImage> {
   const cached = imageCache.get(task.id);
   if (cached) return cached;
-  const blob = await drawExchangeImage(task);
-  const entry = { url: URL.createObjectURL(blob), blob };
-  const previous = imageCache.get(task.id);
-  if (previous) URL.revokeObjectURL(previous.url);
-  imageCache.set(task.id, entry);
-  return entry;
+  const pending = inflightImages.get(task.id);
+  if (pending) return pending;
+  const creating = (async () => {
+    const blob = await drawExchangeImage(task);
+    const entry = { url: URL.createObjectURL(blob), blob };
+    const previous = imageCache.get(task.id);
+    if (previous) URL.revokeObjectURL(previous.url);
+    imageCache.set(task.id, entry);
+    return entry;
+  })();
+  inflightImages.set(task.id, creating);
+  try {
+    return await creating;
+  } finally {
+    inflightImages.delete(task.id);
+  }
 }
 
 export function clearExchangeImageCache(): void {