[rest_gateway] Raise REST gateway gRPC max receive message size above 4MB default (#2466)

## Related Issues
- #2467

## Summarize your change.
GetJobs on a busy facility can return tens of MB (35MB observed on
prod), exceeding gRPC's 4MB default and failing with "received message
larger than max". Set MaxCallRecvMsgSize to 256MB, overridable via

Author: ramonfigueiredo

rest_gateway/opencue_gateway/main.go

@@ -48,6 +48,7 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"strconv"
 	"strings"
 
 	"github.com/golang-jwt/jwt/v5"
@@ -203,8 +204,21 @@ func run() error {
 	// Initialize gRPC-gateway multiplexer for HTTP-to-gRPC translation
 	mux := runtime.NewServeMux()
 
-	// Configure gRPC connection options (using insecure for internal network)
-	opts := []grpc.DialOption{grpc.WithTransportCredentials(insecure.NewCredentials())}
+	// Configure gRPC connection options (using insecure for internal network).
+	// Raise the max receive message size above gRPC's 4MB default so large list
+	// responses (e.g. GetJobs on a busy production facility — tens of MB) aren't
+	// rejected with "received message larger than max". Override via
+	// GRPC_MAX_RECV_MSG_MB (megabytes).
+	maxRecvMsgBytes := 256 * 1024 * 1024 // 256 MB default
+	if v := os.Getenv("GRPC_MAX_RECV_MSG_MB"); v != "" {
+		if mb, err := strconv.Atoi(v); err == nil && mb > 0 {
+			maxRecvMsgBytes = mb * 1024 * 1024
+		}
+	}
+	opts := []grpc.DialOption{
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+		grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(maxRecvMsgBytes)),
+	}
 
 	// Register all gRPC interface handlers
 	if err := registerGRPCHandlers(ctx, mux, grpcServerEndpoint, opts); err != nil {