feat(knowledge): add short-term ask memory

backend/script/sql/update/aihr_20260717_learning_closure_mysql8.sql

@@ -8,7 +8,7 @@ SET @content_version_exists = (
   WHERE table_schema = @aihr_schema AND table_name = 'aihr_practice_assignment' AND column_name = 'content_version'
 );
 SET @content_version_ddl = IF(@content_version_exists = 0,
-  'ALTER TABLE aihr_practice_assignment ADD COLUMN content_version varchar(30) DEFAULT ''v1'' COMMENT ''派发内容版本'' AFTER request_key',
+  'ALTER TABLE aihr_practice_assignment ADD COLUMN content_version varchar(30) DEFAULT ''v1'' COMMENT ''派发内容版本''',
   'SELECT 1');
 PREPARE aihr_content_version_stmt FROM @content_version_ddl;
 EXECUTE aihr_content_version_stmt;

backend/script/sql/update/aihr_20260718_knowledge_conversation_mysql8.sql

@@ -0,0 +1,17 @@
+-- 问师傅短期多轮会话。只保存最近六轮的脱敏截断 JSON，30 分钟不活跃过期。
+
+CREATE TABLE IF NOT EXISTS `aihr_knowledge_conversation` (
+  `id` bigint NOT NULL AUTO_INCREMENT COMMENT '主键',
+  `tenant_id` varchar(20) NOT NULL COMMENT '租户编号',
+  `app_id` bigint NOT NULL COMMENT '内部调用应用ID',
+  `user_id` bigint NOT NULL COMMENT '内部用户ID',
+  `conversation_id` varchar(64) NOT NULL COMMENT '客户端随机会话ID',
+  `version` bigint NOT NULL DEFAULT 0 COMMENT '乐观并发版本',
+  `context_json` json DEFAULT NULL COMMENT '最近六轮脱敏短期上下文',
+  `expires_time` datetime NOT NULL COMMENT '不活跃过期时间',
+  `create_time` datetime NOT NULL COMMENT '创建时间',
+  `update_time` datetime NOT NULL COMMENT '更新时间',
+  PRIMARY KEY (`id`),
+  UNIQUE KEY `uk_aihr_knowledge_conversation` (`tenant_id`, `app_id`, `user_id`, `conversation_id`),
+  KEY `idx_aihr_knowledge_conversation_expire` (`tenant_id`, `expires_time`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci COMMENT='知识问答短期会话';

backend/script/sql/update/aihr_20260718_release_collation_compat_mysql8.sql

@@ -25,6 +25,8 @@ SET @aihr_release_ddl := CONCAT('ALTER TABLE `aihr_knowledge_query_log` CONVERT
 PREPARE aihr_release_stmt FROM @aihr_release_ddl; EXECUTE aihr_release_stmt; DEALLOCATE PREPARE aihr_release_stmt;
 SET @aihr_release_ddl := CONCAT('ALTER TABLE `aihr_knowledge_admin_audit` CONVERT TO CHARACTER SET utf8mb4 COLLATE ', @aihr_release_collation);
 PREPARE aihr_release_stmt FROM @aihr_release_ddl; EXECUTE aihr_release_stmt; DEALLOCATE PREPARE aihr_release_stmt;
+SET @aihr_release_ddl := CONCAT('ALTER TABLE `aihr_knowledge_conversation` CONVERT TO CHARACTER SET utf8mb4 COLLATE ', @aihr_release_collation);
+PREPARE aihr_release_stmt FROM @aihr_release_ddl; EXECUTE aihr_release_stmt; DEALLOCATE PREPARE aihr_release_stmt;
 
 SET @aihr_release_ddl := CONCAT('ALTER TABLE `aihr_learning_question` CONVERT TO CHARACTER SET utf8mb4 COLLATE ', @aihr_release_collation);
 PREPARE aihr_release_stmt FROM @aihr_release_ddl; EXECUTE aihr_release_stmt; DEALLOCATE PREPARE aihr_release_stmt;