feat(puzzle): 优化二维码生成与去重逻辑

- 避免重复上传已存在的微信小程序二维码
- 在去重检测中跳过 dateStr 字段以提高准确性
- 添加文件存在性检查，减少不必要的上传操作
- 记录并返回已存在文件的访问 URL
- 提升 puzzle 服务的性能与资源利用率

src/main/java/com/ycwl/basic/puzzle/util/PuzzleDuplicationDetector.java

@@ -25,7 +25,7 @@ import java.util.stream.Collectors;
 @Component
 @RequiredArgsConstructor
 public class PuzzleDuplicationDetector {
-
+    private final Set<String> skippedElementKeys = Set.of("dateStr");
     private final PuzzleGenerationRecordMapper recordMapper;
 
     /**
@@ -50,6 +50,9 @@ public class PuzzleDuplicationDetector {
             StringBuilder sb = new StringBuilder();
             for (int i = 0; i < sortedKeys.size(); i++) {
                 String key = sortedKeys.get(i);
+                if (skippedElementKeys.contains(key)) {
+                    continue;
+                }
                 String value = finalData.get(key);
                 sb.append(key).append(":").append(value != null ? value : "");
                 if (i < sortedKeys.size() - 1) {