test(gbrain-sync): stub pgrep so the pin case is hermetic

The only non-dry-run --code-only child hits #1734's PATH-resolved
autopilot probe. A live host daemon is a correct refuse; the test
cannot inject processRunning. Neutralize pgrep in the fixture bindir
instead of adding a production env hatch.

Co-authored-by: Cursor <cursoragent@cursor.com>

test/gstack-gbrain-sync.test.ts

@@ -192,6 +192,13 @@ case "$*" in
 esac
 `);
     chmodSync(join(bindir, "gbrain"), 0o755);
+    // #2685: this case is a real (non-dry-run) --code-only child, so it hits
+    // detectAutopilot's PATH-resolved `pgrep -f "gbrain autopilot"`. A live
+    // host autopilot is a correct #1734 refuse — the test cannot inject
+    // processRunning. Stub pgrep to "no match" so the pin is about the
+    // symlink, not the operator's daemon. Do not add a production env hatch.
+    writeFileSync(join(bindir, "pgrep"), "#!/bin/sh\nexit 1\n");
+    chmodSync(join(bindir, "pgrep"), 0o755);
 
     const r = spawnSync("bun", [SCRIPT, "--code-only", "--quiet"], {
       encoding: "utf-8",