feat(settings): agent.sessionDir setting shown on settings page

null keeps the deployment default (AGENT_SESSION_DIR / DATA_DIR/agent-sessions).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/contracts/src/settings.ts

@@ -98,6 +98,11 @@ export const AgentRuntimeSettings = z.object({
     .max(24 * 30),
   /** fake 模式脚本(JSON,FakeScript 的可序列化子集);null 用内置演示脚本 */
   fakeScript: z.string().max(100_000).nullable(),
+  /**
+   * Agent JSONL 会话目录(绝对路径,api 与 worker 进程都要能读写);
+   * null = 部署默认(环境变量 AGENT_SESSION_DIR,缺省 DATA_DIR/agent-sessions)
+   */
+  sessionDir: z.string().max(1024).regex(/^\//, "必须是绝对路径").nullable(),
 });
 export type AgentRuntimeSettings = z.infer<typeof AgentRuntimeSettings>;
 
@@ -168,6 +173,7 @@ export const DEFAULT_SETTINGS: GlobalSettings = {
     goalPollSec: 60,
     goalWaitHours: 72,
     fakeScript: null,
+    sessionDir: null,
   },
   metadata: { tmdbApiKeySecretRef: null, tmdbBaseUrl: null },
 };