feat: add --public-url flag for reverse proxy deployments

Add flag to specify public-facing domain when relay is behind
a reverse proxy that terminates TLS.

Usage:
  ./bin/relay --public-url nostr-grpc.x.bdw.to

When set, the index page displays:
- gRPC: nostr-grpc.x.bdw.to:50051
- Connect: https://nostr-grpc.x.bdw.to
- WebSocket: wss://nostr-grpc.x.bdw.to

When not set, falls back to local addresses (:50051, :8080)
for development environments.

0 files changed, 0 insertions, 0 deletions