Optimize code. Add kdoc.

src/main/resources/db/migration/master/V1_0_0_231019__Add_table_'t_user'.sql

@@ -5,7 +5,7 @@ create table if not exists t_user
     id                     bigint      not null primary key,
     username               varchar(20) not null comment '用户名',
     password               char(70)    not null comment '密码',
-    verify                 varchar(50) null comment '验证信息',
+    verify                 varchar(144) null comment '验证信息',
     locking                int         not null comment '锁定',
     expiration             datetime comment '过期时间',
     credentials_expiration datetime comment '认证过期时间',

src/main/resources/db/migration/master/V1_0_0_231104__Add_table_'t_user_info'.sql

@@ -4,7 +4,7 @@ create table if not exists t_user_info
 (
     id          bigint       not null primary key,
     user_id     bigint       not null comment '用户ID',
-    nickname    varchar(50)  null comment '昵称',
+    nickname    varchar(50)  not null comment '昵称',
     avatar      text         null comment '头像',
     email       varchar(100) not null comment '邮箱',
     create_time datetime     not null default (utc_timestamp()) comment '创建时间',

src/main/resources/templates/email-verify-account-cn.vm

@@ -5,7 +5,7 @@
     <meta name="viewport"
           content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
     <meta http-equiv="X-UA-Compatible" content="ie=edge">
-    <title>激活您的账号</title>
+    <title>验证您的账号</title>
     <style>
         * {
             margin: 0;