feat(i18n): 新增多语言国际化支持

引入 II18nService 与 I18nServiceImpl，使 AppleService 及全局异常处理器可按 Accept-Language 返回本地化错误信息；ErrorCode 新增 getCodeAsString；数据库连接改为 keyborad_db。

src/main/resources/application-dev.yml

@@ -1,7 +1,7 @@
 spring:
   datasource:
     driver-class-name: org.postgresql.Driver
-    url: jdbc:postgresql://localhost:5432/postgres
+    url: jdbc:postgresql://localhost:5432/keyborad_db
     username: root
     password: 123asd
 

src/main/resources/mapper/I18nMessageMapper.xml

@@ -13,4 +13,8 @@
     <!--@mbg.generated-->
     id, code, "locale", message
   </sql>
+
+  <select id="selectByCodeAndLocale" resultMap="BaseResultMap">
+      SELECT * FROM "i18n_message" WHERE code = #{code,jdbcType=VARCHAR} AND locale = #{locale,jdbcType=VARCHAR}
+    </select>
 </mapper>