Enforce session workspace boundaries

frontend/app/app/api/chat/route.ts

@@ -9,6 +9,8 @@ import {
 import {
 	accountSessionInputRoot,
 	accountSessionOutputRoot,
+	accountSessionRoot,
+	accountSessionScratchpadRoot,
 	getCurrentAccount,
 } from "@/lib/claw-auth";
 
@@ -274,17 +276,26 @@ async function getLastUserText(
 
 async function ensureSessionDirectories(accountId: string, sessionId: string) {
 	await Promise.all([
+		mkdir(accountSessionRoot(accountId, sessionId), { recursive: true }),
 		mkdir(accountSessionInputRoot(accountId, sessionId), { recursive: true }),
 		mkdir(accountSessionOutputRoot(accountId, sessionId), { recursive: true }),
+		mkdir(accountSessionScratchpadRoot(accountId, sessionId), {
+			recursive: true,
+		}),
 	]);
 }
 
 function renderSessionRuntimeContext(accountId: string, sessionId: string) {
 	return [
-		"[当前会话目录]",
+		"[当前 session 工作区]",
+		`- session_root: ${accountSessionRoot(accountId, sessionId)}`,
 		`- 输入目录: ${accountSessionInputRoot(accountId, sessionId)}`,
 		`- 输出目录: ${accountSessionOutputRoot(accountId, sessionId)}`,
-		"如需保存本轮任务产物，请优先写入输出目录。",
+		`- 临时目录: ${accountSessionScratchpadRoot(accountId, sessionId)}`,
+		"当前 session 目录是默认可写工作区。",
+		"交付产物必须优先写入输出目录。",
+		"临时脚本、缓存和中间结果必须写入临时目录。",
+		"可以读取完成任务所需的外部资料，但不要修改平台服务代码目录。",
 	].join("\n\n");
 }