feat: add Connect (gRPC over HTTP/JSON) support

Connect integration:
- Buf Connect codegen added to buf.gen.yaml
- Connect handler wraps gRPC server
- Serves on same port as WebSocket (:8080)
- HTTP/2 with h2c for cleartext HTTP/2

Now serving THREE protocols:
1. gRPC (native) on :50051 - binary, high performance
2. Connect on :8080/nostr.v1.NostrRelay/* - HTTP/JSON, browser compatible
3. WebSocket on :8080/ - Nostr standard protocol

All three protocols share:
- Same storage layer
- Same subscription manager
- Same validation logic

Browser-friendly! Call gRPC methods with fetch() or curl.

1 files changed, 16 insertions, 2 deletions

diff --git a/cmd/relay/main.go b/cmd/relay/main.go
index 53296b9..9cf6ad6 100644
--- a/cmd/relay/main.go
+++ b/cmd/relay/main.go
@@ -11,9 +11,14 @@ import (
 
         "context"
 
+        "connectrpc.com/connect"
+        "golang.org/x/net/http2"
+        "golang.org/x/net/http2/h2c"
         "google.golang.org/grpc"
 
         pb "northwest.io/nostr-grpc/api/nostr/v1"
+        "northwest.io/nostr-grpc/api/nostr/v1/nostrv1connect"
+        connecthandler "northwest.io/nostr-grpc/internal/handler/connect"
         grpchandler "northwest.io/nostr-grpc/internal/handler/grpc"
         wshandler "northwest.io/nostr-grpc/internal/handler/websocket"
         "northwest.io/nostr-grpc/internal/storage"
@@ -39,7 +44,14 @@ func main() {
         grpcHandler := grpchandler.NewServer(store)
         grpcHandler.SetSubscriptionManager(subManager)
 
+        connectHandler := connecthandler.NewHandler(grpcHandler)
+
+        mux := http.NewServeMux()
+        path, handler := nostrv1connect.NewNostrRelayHandler(connectHandler, connect.WithInterceptors())
+        mux.Handle(path, handler)
+
         wsHandler := wshandler.NewHandler(store, subManager)
+        mux.Handle("/", wsHandler)
 
         grpcLis, err := net.Listen("tcp", *grpcAddr)
         if err != nil {
@@ -51,11 +63,13 @@ func main() {
 
         httpServer := &http.Server{
                 Addr:    *wsAddr,
-                Handler: wsHandler,
+                Handler: h2c.NewHandler(mux, &http2.Server{}),
         }
 
         log.Printf("gRPC server listening on %s", *grpcAddr)
-        log.Printf("WebSocket server listening on %s", *wsAddr)
+        log.Printf("HTTP server listening on %s", *wsAddr)
+        log.Printf("  - Connect (gRPC-Web) at %s/nostr.v1.NostrRelay/*", *wsAddr)
+        log.Printf("  - WebSocket (Nostr) at %s/", *wsAddr)
         log.Printf("Database: %s", *dbPath)
 
         sigChan := make(chan os.Signal, 1)