Fix nil metrics in server.go by passing metrics.NewNoopMetrics() to NewExporters

Agent-Logs-Url: https://github.com/github/github-mcp-server/sessions/53221b0b-abb4-4138-a147-3ce9e13b379a

Co-authored-by: mattdholloway <918573+mattdholloway@users.noreply.github.com>

Author: Copilot

pkg/http/server.go

@@ -18,6 +18,7 @@ import (
 	"github.com/github/github-mcp-server/pkg/inventory"
 	"github.com/github/github-mcp-server/pkg/lockdown"
 	"github.com/github/github-mcp-server/pkg/observability"
+	"github.com/github/github-mcp-server/pkg/observability/metrics"
 	"github.com/github/github-mcp-server/pkg/scopes"
 	"github.com/github/github-mcp-server/pkg/translations"
 	"github.com/github/github-mcp-server/pkg/utils"
@@ -107,7 +108,7 @@ func RunHTTPServer(cfg ServerConfig) error {
 
 	featureChecker := createHTTPFeatureChecker()
 
-	obs, err := observability.NewExporters(logger, nil)
+	obs, err := observability.NewExporters(logger, metrics.NewNoopMetrics())
 	if err != nil {
 		return fmt.Errorf("failed to create observability exporters: %w", err)
 	}