feat: vendor console — tenant list, create wizard, detail page

Implements Task 9: shared components (ServerStatusBadge, UsageIndicator,
platform.module.css, tierColor utility) and full vendor console pages
(VendorTenantsPage, CreateTenantPage, TenantDetailPage). Build passes cleanly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/src/utils/tier.ts

@@ -1,20 +1,9 @@
-export type TierColor = 'primary' | 'success' | 'warning' | 'error' | 'auto';
-
-export function tierColor(tier: string): TierColor {
+/** Map a tier name to a Badge color. */
+export function tierColor(tier: string): 'primary' | 'success' | 'warning' | 'error' | 'running' | 'auto' {
   switch (tier?.toUpperCase()) {
-    case 'BUSINESS':
-    case 'ENTERPRISE':
-      return 'success';
-    case 'HIGH':
-    case 'PRO':
-      return 'primary';
-    case 'MID':
-    case 'STARTER':
-      return 'warning';
-    case 'LOW':
-    case 'FREE':
-      return 'auto';
-    default:
-      return 'auto';
+    case 'ENTERPRISE': return 'success';
+    case 'PROFESSIONAL': return 'primary';
+    case 'STARTER': return 'warning';
+    default: return 'auto';
   }
 }