Update documentation structure and enhance API descriptions

- Revised README.md to provide a clearer documentation structure for multiple mini programs, including a new table of contents.
- Added references to common authentication documentation in both the remove watermark API and README files.
- Improved clarity of the login interface description and error handling messages in the remove watermark API documentation.

docs/sql/smoke.sql

@@ -0,0 +1,16 @@
+-- 戒烟/抽烟记录主表
+-- 注意：该表字段来自旧系统（createtime/updatetime/deletetime 为秒级时间戳）
+
+CREATE TABLE `fa_smoke_log` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  `uid` int(11) NOT NULL COMMENT '用户ID',
+  `smoke_time` date DEFAULT NULL COMMENT '抽烟时间',
+  `remark` text COMMENT '抽烟原因',
+  `createtime` int(11) DEFAULT NULL COMMENT '创建时间',
+  `updatetime` int(11) DEFAULT NULL COMMENT '修改时间',
+  `deletetime` int(11) DEFAULT NULL COMMENT '删除时间',
+  `level` bigint(2) DEFAULT '1' COMMENT '烟瘾程度',
+  `num` int(2) DEFAULT '1' COMMENT '抽烟数量',
+  PRIMARY KEY (`id`,`uid`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='抽烟记录';
+