HSTS was unconditionally tied to hasTls. This is risky: enabling it on a
deployment that later loses TLS locks browsers out until max-age expires.
Add three options under services.hyperhive.gateway.hsts:
enable — bool, default false
maxAge — seconds, default 31536000 (1 year)
includeSubDomains — bool, default true
HSTS header is now only emitted when hsts.enable = true.
5264ef7d5e