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.

agent/copilot_acp_client.py

@@ -46,6 +46,47 @@ def _resolve_args() -> list[str]:
     return shlex.split(raw)
 
 
+def _resolve_home_dir() -> str:
+    """Return a stable HOME for child ACP processes."""
+
+    try:
+        from hermes_constants import get_subprocess_home
+
+        profile_home = get_subprocess_home()
+        if profile_home:
+            return profile_home
+    except Exception:
+        pass
+
+    home = os.environ.get("HOME", "").strip()
+    if home:
+        return home
+
+    expanded = os.path.expanduser("~")
+    if expanded and expanded != "~":
+        return expanded
+
+    try:
+        import pwd
+
+        resolved = pwd.getpwuid(os.getuid()).pw_dir.strip()
+        if resolved:
+            return resolved
+    except Exception:
+        pass
+
+    # Last resort: /tmp (writable on any POSIX system). Avoids crashing the
+    # subprocess with no HOME; callers can set HERMES_HOME explicitly if they
+    # need a different writable dir.
+    return "/tmp"
+
+
+def _build_subprocess_env() -> dict[str, str]:
+    env = os.environ.copy()
+    env["HOME"] = _resolve_home_dir()
+    return env
+
+
 def _jsonrpc_error(message_id: Any, code: int, message: str) -> dict[str, Any]:
     return {
         "jsonrpc": "2.0",
@@ -382,6 +423,7 @@ class CopilotACPClient:
                 text=True,
                 bufsize=1,
                 cwd=self._acp_cwd,
+                env=_build_subprocess_env(),
             )
         except FileNotFoundError as exc:
             raise RuntimeError(