feat: Complete rewrite as Next.js admin dashboard

Major transformation from FastAPI telemetry service to Next.js admin dashboard:

- Next.js 15 App Router with TypeScript
- Prisma ORM with PostgreSQL (same schema, new client)
- TanStack Query for data fetching
- Tailwind CSS + shadcn/ui components
- Admin dashboard with:
  - Dashboard stats overview
  - Customer management (list, detail, edit)
  - Order management (list, create, detail, logs)
  - Server monitoring (grid view)
  - Subscription management

Pages implemented:
- /admin (dashboard)
- /admin/customers (list + [id] detail)
- /admin/orders (list + [id] detail with SSE logs)
- /admin/servers (grid view)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.env.local.example

@@ -0,0 +1,24 @@
+# Database
+DATABASE_URL="postgresql://letsbe:letsbe@localhost:5432/letsbe_hub"
+
+# NextAuth.js
+NEXTAUTH_URL="http://localhost:3000"
+NEXTAUTH_SECRET="your-secret-key-here-change-in-production"
+
+# Stripe (Phase 5)
+# STRIPE_SECRET_KEY="sk_test_..."
+# STRIPE_WEBHOOK_SECRET="whsec_..."
+
+# Entri DNS API (Phase 3)
+# ENTRI_APP_ID="..."
+# ENTRI_SECRET="..."
+
+# Runner Authentication
+RUNNER_TOKEN="change-me-in-production"
+
+# Admin Setup
+ADMIN_EMAIL="admin@letsbe.solutions"
+ADMIN_PASSWORD="change-me-in-production"
+
+# Hub Internal URL (for runners)
+HUB_INTERNAL_URL="http://localhost:3000"