fix: remove duplicate HAProxy widget registration from main.go

The dashboard plugin had its own copy of HAProxy widget definitions
that main.go called directly. Now that the haproxy plugin is imported
and registers those same widgets during Initialize(), the explicit
call in main.go caused a "widget type already registered" conflict.

Removed the dashboardPlugin.RegisterHAProxyWidgets() call and
converted the dashboard import to a blank import.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: sarg3nt

gearbox/cmd/server/main.go

@@ -35,7 +35,7 @@ import (
 	// Import plugins - blank identifier triggers init() registration
 	_ "github.com/sarg3nt/gearbox/internal/plugins/alerts"
 	_ "github.com/sarg3nt/gearbox/internal/plugins/certificates"
-	dashboardPlugin "github.com/sarg3nt/gearbox/internal/plugins/dashboard"
+	_ "github.com/sarg3nt/gearbox/internal/plugins/dashboard"
 	_ "github.com/sarg3nt/gearbox/internal/plugins/haproxy"
 	_ "github.com/sarg3nt/gearbox/internal/plugins/logs"
 	_ "github.com/sarg3nt/gearbox/internal/plugins/metrics"
@@ -372,11 +372,6 @@ func main() {
 		log.Fatalf("Failed to register core widgets: %v", err)
 	}
 
-	// Register HAProxy-specific widgets
-	if err := dashboardPlugin.RegisterHAProxyWidgets(widgetRegistry); err != nil {
-		log.Fatalf("Failed to register HAProxy widgets: %v", err)
-	}
-
 	dashboardHandler := handler.NewDashboardHandler(
 		dashboardStorage,
 		widgetRegistry,