feat: 知识库文件夹/模板、技能压缩设置与摘要窗口调优

- 知识库新增文件夹与模板支持（模型/仓储/服务/迁移），前端知识管理组件
- 岗位管理模型与接口完善
- 技能新增压缩设置页与相关存储/工具能力
- 系统设置扩展配置项
- 摘要中间件 keep 窗口改用 token 预算（16000），减少重复压缩

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

offline-backend-20260512/backend/scripts/sql/column_additions_mysql.sql

@@ -94,6 +94,10 @@ CALL _add_column_if_missing('agent_favorites', 'position_id', 'VARCHAR(64) NULL
 CALL _add_column_if_missing('scheduled_task_subscriptions', 'origin', "VARCHAR(16) NOT NULL DEFAULT 'user'");
 CALL _add_column_if_missing('scheduled_task_subscriptions', 'position_id', 'VARCHAR(64) NULL DEFAULT NULL');
 
+-- knowledge_notes.folder: 用户自建目录(斜杠分隔路径),驱动产品目录树;NULL=未归类。
+-- (knowledge_folders / knowledge_extract_templates 为【新表】,由 create_all 自动建,无需在此补列。)
+CALL _add_column_if_missing('knowledge_notes', 'folder', 'VARCHAR(512) NULL DEFAULT NULL');
+
 -- ---- 清理临时存储过程 --------------------------------------------------------
 DROP PROCEDURE IF EXISTS _add_column_if_missing;
 
@@ -111,6 +115,20 @@ PREPARE stmt FROM @idx_ddl;
 EXECUTE stmt;
 DEALLOCATE PREPARE stmt;
 
+-- ---- knowledge_notes.folder 索引(幂等) --------------------------------------
+SET @idx_exists = (
+    SELECT COUNT(*) FROM information_schema.statistics
+     WHERE table_schema = DATABASE()
+       AND table_name = 'knowledge_notes'
+       AND index_name = 'ix_knowledge_notes_folder'
+);
+SET @idx_ddl = IF(@idx_exists = 0,
+    'CREATE INDEX `ix_knowledge_notes_folder` ON `knowledge_notes` (`folder`(191))',
+    'SELECT ''SKIPPED  ix_knowledge_notes_folder (already exists)'' AS result');
+PREPARE stmt FROM @idx_ddl;
+EXECUTE stmt;
+DEALLOCATE PREPARE stmt;
+
 -- ---- 执行后自检:确认本批次涉及的列都已存在 ---------------------------------
 SELECT table_name, column_name
   FROM information_schema.columns