When the gateway serves internal-CA HTTPS (gateway.tls=internal), other devices
must trust Caddy's root CA to accept *.lan HTTPS. Surface that from the dashboard
instead of hand-copying root.crt around.
- API: GET /gateway/ca.crt returns the public root cert (PEM) as a download,
sourced from Caddy's admin API (/pki/ca/local — matches the running gateway)
with an on-disk root.crt fallback. 404 unless tls=internal. GatewayInfo gains
`tls` and `ca_fingerprint` (SHA-256, for out-of-band verification). The CA
private key is never exposed — only the public root.
- UI: a "CA cert" button in the Gateway panel, shown only when tls=internal,
linking to the download with the fingerprint in its tooltip.
- Tests for the tls=off defaults and the 404-without-internal-tls path; docs note
the button + endpoint.
Paul Payne
fc5802d823