The catch-all, the dashboard and the hive-domain vhost were built in
vhosts.nix with the listen set, TLS attrs and headers applied by hand.
They are declared under services.hyperhive.gateway.vhosts now, so every
vhost behind the gateway goes through declared-vhosts.nix.
Two gateway-side rules cover what the catch-all needed: a vhost can set
securityHeaders = false (the catch-all only returns 444), and `default`
is rendered at mkDefault priority so an operator's own default vhost
still wins. The matrix discovery locations are unchanged.
The rendered nginx vhosts are unchanged.
Ten service modules (forge, matrix chat, authelia, grafana, otel, nats,
swarm-ui, victorialogs, victoriametrics, bao UI) wrote
services.nginx.virtualHosts themselves, each applying the gateway's
listen set, per-name TLS attrs and security headers by hand. They now
declare services.hyperhive.gateway.vhosts.<name> with only their own
locations and options; ./declared-vhosts.nix renders it into the nginx
vhost with listen, TLS and headers added.
An eval assertion refuses a declared vhost that sets listen, addSSL,
onlySSL, enableACME, useACMEHost, sslCertificate or sslCertificateKey,
and one declared while the gateway is off. nats' own leaf is the new
`certificate` field. The rendered nginx vhosts are unchanged.
