refactor(portal): extract shared partner types and data composables

Move partner domain types out of data/customers.ts into types/partner.ts so the fixture data exports can be removed later without breaking type imports. Add usePartnerTenants / usePartnerMrr composables wrapping the shared-key partner fetches.

apps/portal/data/customers.ts

@@ -2,23 +2,9 @@
 // orgs. Numbers seeded to match partner-screens.jsx (the canonical design
 // source) line for line: same customer set, same MRR, seats, status, mark.
 
-export type CustomerStatus = 'healthy' | 'attention' | 'past_due' | 'trial' | 'suspended'
-
-export interface CustomerOrg {
-  id: string
-  name: string
-  domain: string
-  plan: 'starter' | 'business' | 'enterprise'
-  planLabel: 'Starter' | 'Business' | 'Enterprise'
-  seats: { used: number; total: number }
-  health: number
-  status: CustomerStatus
-  mrrDkk: number
-  brandColor: string
-  industry: string
-  createdOn: string
-  since: string
-}
+// Types moved to ~/types/partner so the fixture *data* below can be deleted
+// page-by-page (as each goes real) without breaking type-only importers.
+import type { CustomerOrg } from '~/types/partner'
 
 export const partner = {
   id: 'p-nordicmsp',