feat(portal): customer-admin surface on real data + Stripe billing + session resilience

Access & navigation
- Gate partner-mode strictly to partner staff so admins/end-users never inherit
  leftover partner-view state; purge stale session entry on hydrate.
- Role-driven admin entry: useMe.isTenantAdmin, Admin/Personal tiles in the app
  launcher, and an /admin route guard in the global middleware (fail closed).
- Drop the duplicate user identity block from the sidebar footer.

Admin pages on real data
- New tenant-scoped, membership-gated endpoints: GET /tenants/:slug/{audit,users,
  invoices}; useTenant composable resolves the active workspace + subscription.
- Dashboard: real seats, spend (cycle-normalized + minor-units), plan, renewal,
  and recent audit; unbacked sections removed.
- Users & groups: real members; Groups/Invitations/Service accounts shown as
  honest "coming soon".
- Subscription & invoices: real plan hero, invoice history, and billing details.

Stripe payment method (Elements + SetupIntent)
- StripeClient: publishable key + getDefaultCard/createSetupIntent/setDefaultCard.
- CustomerBillingController + BillingService methods (ensure-customer on demand).
- Portal: PaymentMethodModal, useStripeJs (CDN load), proxies; hidePostalCode.

Editable billing details & whitelabel branding
- PATCH /tenants/:slug/billing-info (narrow: company/VAT/country/email).
- TenantBranding schema/service + GET/PUT /tenants/:slug/branding: real product
  name, accent colour, and per-tenant email-template overrides.
- Branding preview + sidebar workspace mark wired to real name/plan/seats/colour
  with YIQ auto-contrast (readableOn util).

Session resilience
- Request offline_access so Authentik issues a refresh token (automaticRefresh).
- Silent refresh + single retry on 401 for writes (useApiFetch, incl. partner
  pages) and reads (useMe.fetchMe) — no redirect, no lost input.
- Modal backdrop closes only on press+release on the backdrop (no more
  drag-select-to-close).

services/platform-api/src/billing/billing.module.ts

@@ -10,6 +10,7 @@ import { Subscription, SubscriptionSchema } from '../schemas/subscription.schema
 import { Tenant, TenantSchema } from '../schemas/tenant.schema.js'
 import { UsersModule } from '../users/users.module.js'
 import { BillingService } from './billing.service.js'
+import { CustomerBillingController } from './customer-billing.controller.js'
 import { OperatorBillingController } from './operator-billing.controller.js'
 import { PartnerBillingController } from './partner-billing.controller.js'
 import { PayoutWorker } from './payout.worker.js'
@@ -29,7 +30,12 @@ import { StripeWebhookController } from './stripe-webhook.controller.js'
     IntegrationsModule,
     UsersModule,
   ],
-  controllers: [PartnerBillingController, OperatorBillingController, StripeWebhookController],
+  controllers: [
+    PartnerBillingController,
+    OperatorBillingController,
+    CustomerBillingController,
+    StripeWebhookController,
+  ],
   providers: [BillingService, PayoutWorker],
 })
 export class BillingModule {}