## Summary
Operator listener configuration currently rejects HTTP URLs, preventing
delivery to sibling services over internal HTTP connections. Accept HTTP
and HTTPS delivery URLs while retaining the existing pubkey,
duplicate-route, and URL restrictions.
Add configuration coverage for internal hostnames and custom ports,
verify signed delivery through the real HTTP client, and include the
listener suite in both unit-test runners. Shared NIP-98 signing and push
gateway code are unchanged.
### Related issue
Related: #7934 refactors operator listener delivery tests. No matching
open issue found.
### Testing
- `cargo test -p buzz-relay --lib operator_listener`: 13 passed,
including signed HTTP delivery and redirect rejection.
- `cargo fmt --all -- --check`, shell syntax, Justfile parsing, and diff
whitespace checks passed.
- `just test`: passed.
- `just ci`: stopped at mobile analysis with an existing undefined
`buzzDevPushAppProfile` in
`mobile/test/features/settings/notification_toggle_test.dart:81`.
Workspace and native desktop formatting/Clippy, desktop frontend checks,
and web checks passed. The mobile file is unchanged by this PR.
Locally verified with a spiked listener client
Signed-off-by: jsibbison-square <jsibbison@squareup.com>
8599efb6a3