style: standardize quotation marks from double to single in Python files for consistency

Author: Rasic2

evaluate/experiments/threads/database_search/database_search.json

@@ -218,4 +218,4 @@
       "\u7ed3\u679c\u6570\u91cf\u6b63\u786e"
     ]
   }
-]
+]

evaluate/experiments/threads/database_search/database_search.py

@@ -7,4 +7,4 @@
     print('🚀 人类模拟器启动')
     print('=' * 50)
 
-    asyncio.run(evaluation_threads_task("database_search.json", max_turn_count=5))
+    asyncio.run(evaluation_threads_task('database_search.json', max_turn_count=5))

evaluate/experiments/threads/structure_generate/structure_generate.py

@@ -8,4 +8,4 @@
     print('🚀 人类模拟器启动')
     print('=' * 50)
 
-    asyncio.run(evaluation_threads_task("structure_generate.json"))
+    asyncio.run(evaluation_threads_task('structure_generate.json'))