fix(sandbox): 子进程环境保留 PATH,编译产物里沙箱任务恢复;编译自检加沙箱启动

清空环境后编译产物在入口按 PATH 解析 --allow-run 失败直接退出,Bangumi 热门、字幕验证码 / 解压等沙箱任务一直报错。

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Cxwgnn2pbzQ7rXv3rq7fei

apps/server/test/sandbox/sandbox.test.ts

@@ -1,13 +1,19 @@
 import { buildFakeTorrent, RAR5_SAMPLE_BASE64, SEVENZIP_SUBTITLE_BASE64, ZIMUKU_CAPTCHA } from "@umt/testkit";
 import { zipSync } from "fflate";
 import { describe, expect, it } from "vitest";
-import { runSandbox, SandboxError } from "../../src/sandbox/client.ts";
+import { runSandbox, SandboxError, sandboxEnv } from "../../src/sandbox/client.ts";
 import { b64encode } from "../../src/sandbox/jobs.ts";
 
 // 沙箱(docs/adr/ADR-005-sandbox.md):子进程撤销全部权限;卡死超时强杀;内存超限强杀;任务错误原样带回
 const enc = (s: string) => new TextEncoder().encode(s);
 
 describe("沙箱子进程", () => {
+  it("子进程环境只带 PATH(编译产物入口要按 PATH 解析 --allow-run 的命令名,没有会直接退出)", () => {
+    const env = sandboxEnv();
+    expect(Object.keys(env)).toEqual(["PATH"]);
+    expect(env.PATH).toBeTruthy();
+  });
+
   it("正常返回;子进程里读文件被拒绝", async () => {
     expect(await runSandbox("self.test", { mode: "ok" })).toEqual({ ok: true });
     await expect(runSandbox("self.test", { mode: "io" })).rejects.toMatchObject({ kind: "job", message: /NotCapable/ });