fix: PR#164审查修复 - P1 count_by_user status参数 + P2 内存分页优化

P1修复:
- voice_library_repository.count_by_user() 增加可选 status 参数
- 修复 list_voices_unified 中 TypeError: count_by_user got unexpected keyword argument 'status'

P2修复:
- 移除 limit=1000 全量拉取，改为直接传递 skip/limit 到仓储层
- 删除冗余的 clone_repository_count() 辅助函数
- 优化统一列表分页逻辑，代码更清晰

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/adapters/sqlalchemy_impl/voice_library_repository.py

@@ -110,15 +110,17 @@ class SQLAlchemyVoiceLibraryRepository:
         self.session.commit()
         return True
 
-    def count_by_user(self, user_id: str) -> int:
-        return (
+    def count_by_user(self, user_id: str, *, status: Optional[str] = None) -> int:
+        query = (
             self.session.query(VoiceLibraryModel)
             .filter(
                 VoiceLibraryModel.user_id == user_id,
                 VoiceLibraryModel.status != "deleted",
             )
-            .count()
         )
+        if status:
+            query = query.filter(VoiceLibraryModel.status == status)
+        return query.count()
 
     @staticmethod
     def _model_to_entity(model: VoiceLibraryModel) -> VoiceLibraryItem: