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.
file_safety now uses profile-aware get_hermes_home(), so the test
fixture must override HERMES_HOME too — otherwise it resolves to the
conftest's isolated tempdir and the hub-cache path doesn't match.