fix(test): harden planner artifact cleanup and profile env fallback

test/scripts/test-planner.test.ts

@@ -3,6 +3,7 @@ import path from "node:path";
 import { describe, expect, it } from "vitest";
 import {
   createExecutionArtifacts,
+  createTempArtifactWriteStream,
   resolvePnpmCommandInvocation,
   resolveVitestFsModuleCachePath,
 } from "../../scripts/test-planner/executor.mjs";
@@ -348,6 +349,24 @@ describe("test planner", () => {
     expect(fs.existsSync(artifactDir)).toBe(false);
   });
 
+  it("keeps fd-backed artifact streams writable after temp cleanup", async () => {
+    const artifacts = createExecutionArtifacts({});
+    const artifactDir = artifacts.ensureTempArtifactDir();
+    const logPath = path.join(artifactDir, "lane.log");
+    const stream = createTempArtifactWriteStream(logPath);
+
+    stream.write("before cleanup\n");
+    artifacts.cleanupTempArtifacts();
+
+    await expect(
+      new Promise((resolve, reject) => {
+        stream.on("error", reject);
+        stream.end("after cleanup\n", resolve);
+      }),
+    ).resolves.toBeNull();
+    expect(fs.existsSync(artifactDir)).toBe(false);
+  });
+
   it("builds a CI manifest with planner-owned shard counts and matrices", () => {
     const manifest = buildCIExecutionManifest(
       {