feat(system): 支持后台维护三语协议

sql/schema.sql

@@ -127,6 +127,17 @@ CREATE TABLE IF NOT EXISTS sys_config (
 CREATE UNIQUE INDEX IF NOT EXISTS uk_sys_config_key ON sys_config (config_key);
 COMMENT ON TABLE sys_config IS '系统配置';
 
+CREATE TABLE IF NOT EXISTS legal_document (
+  id         BIGINT PRIMARY KEY,
+  doc_code   VARCHAR(16)  NOT NULL,              -- terms / privacy
+  lang       VARCHAR(8)   NOT NULL,              -- zh / en / id
+  title      VARCHAR(128) NOT NULL DEFAULT '',
+  content    TEXT         NOT NULL DEFAULT '',
+  updated_at TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+CREATE UNIQUE INDEX IF NOT EXISTS uk_legal_document_code_lang ON legal_document (doc_code, lang);
+COMMENT ON TABLE legal_document IS '服务条款与隐私协议';
+
 CREATE TABLE IF NOT EXISTS sys_operation_log (
   id            BIGINT PRIMARY KEY,
   admin_user_id BIGINT       NOT NULL DEFAULT 0,