Two defensive fixes in gateway/run.py:
1. yaml.safe_load returning None on empty config files (line 12706):
GatewayConfig.from_dict(data) crashes with AttributeError when the YAML
file is empty because safe_load returns None. All 6 other yaml.safe_load
call sites already use `or {}` — this one was missed.
Impact: gateway fails to start with empty --config file.
2. float() on env vars without ValueError guard (lines 3951, 11757, 11805,
11807): HERMES_AGENT_TIMEOUT, HERMES_AGENT_TIMEOUT_WARNING, and
HERMES_AGENT_NOTIFY_INTERVAL are cast via float() directly from
os.getenv(). A typo (e.g. "abc") raises ValueError and crashes the
agent turn or gateway startup.
Impact: single misconfigured env var crashes the entire gateway.
ca87c822ed