fix: set HOME for profile gateway services

[akropp]

Summary

• Set HOME from HERMES_HOME in generated profile gateway s6 run scripts
• Keep profile gateway services from inheriting /root as HOME after s6-setuidgid drops to the hermes user
• Add test coverage for the generated run script

Why

When a per-profile gateway runs under s6 in the Docker container, the generated service script drops privileges with s6-setuidgid hermes but can still inherit HOME=/root. Code paths that resolve state/cache paths through Path.home() or XDG defaults may then attempt to write under /root, causing permission errors for the hermes user. The container main wrapper already normalizes HOME; profile gateway service scripts should do the same.

Test Plan

• python -m pytest tests/hermes_cli/test_service_manager.py -q
• python -m ruff check hermes_cli/service_manager.py tests/hermes_cli/test_service_manager.py

[benbarclay]

Thanks for the catch — #33481 lands the same HOME reset for profile gateway services and extends it to the dashboard service (docker/s6-rc.d/dashboard/run) which has the identical issue. #33481 includes regression tests for both paths and merged as c341a2d. Closing this one in favor of it; full credit to you for spotting the gateway side first.