📝 docs(database): update category table name and comment

- rename "category" table to "goods_category" for better clarity
- update table comment from "分类表" to "商品分类表" to reflect its purpose more accurately

docs/旧数据表.sql

@@ -47,9 +47,9 @@ CREATE TABLE `card` (
   UNIQUE KEY `card_no` (`card_no`) USING BTREE
 ) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ROW_FORMAT=COMPACT COMMENT='卡';
 
--- 分类表
-DROP TABLE IF EXISTS `category`;
-CREATE TABLE `category` (
+-- 商品分类表
+DROP TABLE IF EXISTS `goods_category`;
+CREATE TABLE `goods_category` (
   `id` int NOT NULL AUTO_INCREMENT COMMENT '类别id',
   `name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '类别名称',
   `parent_id` int DEFAULT '0' COMMENT '上级id',