fix(level): 默认返回 punchline 和 hint1 线索提示

未通关用户现在可以查看谐音梗说明和第一个线索提示，
hint2/hint3 仍需通关后才显示。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/modules/level/dto/level-list.dto.ts

@@ -22,10 +22,10 @@ export class LevelListItemDto {
   @ApiProperty({ description: '答案（仅已通关时返回）', nullable: true })
   answer!: string | null;
 
-  @ApiProperty({ description: '谐音梗说明（仅已通关时返回）', nullable: true })
+  @ApiProperty({ description: '谐音梗说明（始终返回）', nullable: true })
   punchline!: string | null;
 
-  @ApiProperty({ description: '线索1（仅已通关时返回）', nullable: true })
+  @ApiProperty({ description: '线索1（始终返回）', nullable: true })
   hint1!: string | null;
 
   @ApiProperty({ description: '线索2（仅已通关时返回）', nullable: true })

src/modules/wechat-game/level-fields.helper.ts

@@ -31,6 +31,7 @@ export function pickLevelImageFields(level: Level): LevelImageFields {
 
 /**
  * Pick image fields with answer/hints masked for non-completed levels.
+ * hint1 is always shown (first clue is the default hint shown to players).
  */
 export function pickLevelImageFieldsMasked(
   level: Level,
@@ -41,8 +42,8 @@ export function pickLevelImageFieldsMasked(
     image1Description: level.image1Description,
     image2Url: level.image2Url,
     image2Description: level.image2Description,
-    punchline: completed ? level.punchline : null,
-    hint1: completed ? level.hint1 : null,
+    punchline: level.punchline,
+    hint1: level.hint1,
     hint2: completed ? level.hint2 : null,
     hint3: completed ? level.hint3 : null,
   };