The relay can use a configurable HTTP(S) gateway delivery URL and signs
the same URL it sends. The gateway verifies NIP-98 against the received
request URL, including authority, port, path and query. App Attest,
scoped grants, replay checks and delivery quotas are unchanged.
Forwarding proxies must preserve Host and supply the original request
scheme through X-Forwarded-Proto. The NIP relay-delivery wording now
defines the configured HTTP(S) URL as the signed URL and labels the
public URL as an example.
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Signed-off-by: Tom Brow <tomb@block.xyz>
781d39510c