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>

frontend-web/src/core/system-settings/api.ts

@@ -247,6 +247,50 @@ export async function updateCitationDisplaySettings(
   return (await response.json()) as CitationDisplaySettings;
 }
 
+export interface SkillCompressionSettings {
+  enabled: boolean;
+  search_top_n: number;
+  keep_index_in_prompt: boolean;
+}
+
+export interface SkillCompressionUpdate {
+  enabled?: boolean;
+  search_top_n?: number;
+  keep_index_in_prompt?: boolean;
+}
+
+export async function loadSkillCompressionSettings(): Promise<SkillCompressionSettings> {
+  const response = await apiFetch(
+    `${getBackendBaseURL()}/api/system-settings/skill-compression`,
+  );
+  if (!response.ok) {
+    throw new Error(
+      `Failed to load skill compression settings: ${response.status}`,
+    );
+  }
+  return (await response.json()) as SkillCompressionSettings;
+}
+
+export async function updateSkillCompressionSettings(
+  body: SkillCompressionUpdate,
+): Promise<SkillCompressionSettings> {
+  const response = await apiFetch(
+    `${getBackendBaseURL()}/api/system-settings/skill-compression`,
+    {
+      method: "PUT",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify(body),
+    },
+  );
+  if (!response.ok) {
+    const detail = await response
+      .json()
+      .catch(() => ({ detail: "Failed to update skill compression" }));
+    throw new Error(detail.detail ?? "Failed to update skill compression");
+  }
+  return (await response.json()) as SkillCompressionSettings;
+}
+
 export interface LogSystemSettings {
   enabled: boolean;
   url: string;