refactor: full-stack restructure with multi-tenancy, workspace management, and K8s diagnostics

- Add Workspace domain (entity, repository, service, handler, DTO)
- Add multi-tenant K8s client with tenant binding and quota management
- Add K8s diagnostics client (instance diagnostics)
- Add authorization middleware (authz package)
- Restructure frontend to feature-based architecture (features/)
- Add User Management page in configuration
- Add AccessDenied page and route guards
- Refactor shared components (form inputs, layout, UI)
- Update Tailwind config for new design system
- Add comprehensive documentation (docs/, tasks/, plans)
- Improve cluster service with better kubeconfig handling
- Add tests for crypto, config, helm client, tenant binding

frontend/src/shared/components/ui/Badge.tsx

@@ -17,15 +17,15 @@ export interface BadgeProps {
 }
 
 const variantStyles: Record<BadgeVariant, string> = {
-  default: "bg-blue-600/20 text-blue-300 border-blue-500/30",
-  success: "bg-green-600/20 text-green-300 border-green-500/30",
-  warning: "bg-yellow-600/20 text-yellow-300 border-yellow-500/30",
-  danger: "bg-red-600/20 text-red-300 border-red-500/30",
-  info: "bg-blue-600/20 text-blue-300 border-blue-500/30",
-  purple: "bg-purple-600/20 text-purple-300 border-purple-500/30",
-  gray: "bg-gray-600/20 text-gray-300 border-gray-500/30",
-  blue: "bg-blue-600/20 text-blue-300 border-blue-500/30",
-  secondary: "bg-gray-700/30 text-gray-200 border-gray-500/40",
+  default: "bg-slate-100 text-slate-700 border-slate-200",
+  success: "bg-emerald-50 text-emerald-700 border-emerald-200",
+  warning: "bg-amber-50 text-amber-700 border-amber-200",
+  danger: "bg-red-50 text-red-700 border-red-200",
+  info: "bg-blue-50 text-blue-700 border-blue-200",
+  purple: "bg-violet-50 text-violet-700 border-violet-200",
+  gray: "bg-slate-100 text-slate-600 border-slate-200",
+  blue: "bg-blue-50 text-blue-700 border-blue-200",
+  secondary: "bg-slate-100 text-slate-700 border-slate-200",
 };
 
 const sizeStyles: Record<BadgeSize, { badge: string; icon: string }> = {