fix: set HOME for Copilot ACP subprocesses

Pass an explicit HOME into Copilot ACP child processes so delegated ACP runs do not fail when the ambient environment is missing HOME.

Prefer the per-profile subprocess home when available, then fall back to HOME, expanduser('~'), pwd.getpwuid(...), and /home/openclaw. Add regression tests for both profile-home preference and clean HOME fallback.

Refs #11068.

tests/agent/test_copilot_acp_client.py

@@ -144,3 +144,60 @@ class CopilotACPClientSafetyTests(unittest.TestCase):
 
 if __name__ == "__main__":
     unittest.main()
+
+
+# ── HOME env propagation tests (from PR #11285) ─────────────────────
+
+from unittest.mock import patch as _patch
+import pytest
+
+
+def _make_home_client(tmp_path):
+    return CopilotACPClient(
+        api_key="copilot-acp",
+        base_url="acp://copilot",
+        acp_command="copilot",
+        acp_args=["--acp", "--stdio"],
+        acp_cwd=str(tmp_path),
+    )
+
+
+def _fake_popen_capture(captured):
+    def _fake(cmd, **kwargs):
+        captured["cmd"] = cmd
+        captured["kwargs"] = kwargs
+        raise FileNotFoundError("copilot not found")
+    return _fake
+
+
+def test_run_prompt_prefers_profile_home_when_available(monkeypatch, tmp_path):
+    hermes_home = tmp_path / "hermes"
+    profile_home = hermes_home / "home"
+    profile_home.mkdir(parents=True)
+
+    monkeypatch.delenv("HOME", raising=False)
+    monkeypatch.setenv("HERMES_HOME", str(hermes_home))
+
+    captured = {}
+    client = _make_home_client(tmp_path)
+
+    with _patch("agent.copilot_acp_client.subprocess.Popen", side_effect=_fake_popen_capture(captured)):
+        with pytest.raises(RuntimeError, match="Could not start Copilot ACP command"):
+            client._run_prompt("hello", timeout_seconds=1)
+
+    assert captured["kwargs"]["env"]["HOME"] == str(profile_home)
+
+
+def test_run_prompt_passes_home_when_parent_env_is_clean(monkeypatch, tmp_path):
+    monkeypatch.delenv("HOME", raising=False)
+    monkeypatch.delenv("HERMES_HOME", raising=False)
+
+    captured = {}
+    client = _make_home_client(tmp_path)
+
+    with _patch("agent.copilot_acp_client.subprocess.Popen", side_effect=_fake_popen_capture(captured)):
+        with pytest.raises(RuntimeError, match="Could not start Copilot ACP command"):
+            client._run_prompt("hello", timeout_seconds=1)
+
+    assert "env" in captured["kwargs"]
+    assert captured["kwargs"]["env"]["HOME"]