fix(kline): stop loading when no unique new history data

When deduplicated new klines are empty, mark hasMoreHistory as false
to prevent infinite loading attempts.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mining-app/lib/presentation/providers/trading_providers.dart

@@ -154,10 +154,17 @@ class KlinesNotifier extends StateNotifier<KlinesState> {
             (k) => !existingTimes.contains(k.time.millisecondsSinceEpoch)
           ).toList();
 
+          // 如果去重后没有新数据，说明已经没有更多历史了
+          if (uniqueNewKlines.isEmpty) {
+            state = state.copyWith(isLoadingMore: false, hasMoreHistory: false);
+            return;
+          }
+
           final combinedKlines = [...uniqueNewKlines, ...state.klines];
           // 按时间排序
           combinedKlines.sort((a, b) => a.time.compareTo(b.time));
 
+          // 判断是否还有更多历史：返回数据少于100条说明到底了
           state = state.copyWith(
             klines: combinedKlines,
             isLoadingMore: false,