feat: consolidate frontend API layer, add query-client, and harden backend Fase 1

Frontend:
- Consolidate duplicate API layers into single src/lib/axios.ts per app
- Remove src/lib/api-client.ts and src/utils/api.ts (admin)
- Add src/lib/query-client.ts with TanStack Query config per app
- Update all imports and auto-import config

Backend:
- Fix organisations.billing_status default to 'trial'
- Fix user_invitations.invited_by_user_id to nullOnDelete
- Add MeResource with separated app_roles and pivot-based org roles
- Add cross-org check to EventPolicy view() and update()
- Restrict EventPolicy create/update to org_admin/event_manager (not org_member)
- Attach creator as org_admin on organisation store
- Add query scopes to Event and UserInvitation models
- Improve factories with Dutch test data
- Expand test suite from 29 to 41 tests (90 assertions)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/portal/auto-imports.d.ts

@@ -375,7 +375,6 @@ import { UnwrapRef } from 'vue'
 declare module 'vue' {
   interface GlobalComponents {}
   interface ComponentCustomProperties {
-    readonly $api: UnwrapRef<typeof import('./src/utils/api')['$api']>
     readonly COOKIE_MAX_AGE_1_YEAR: UnwrapRef<typeof import('./src/utils/constants')['COOKIE_MAX_AGE_1_YEAR']>
     readonly EffectScope: UnwrapRef<typeof import('vue')['EffectScope']>
     readonly acceptHMRUpdate: UnwrapRef<typeof import('pinia')['acceptHMRUpdate']>
@@ -527,7 +526,6 @@ declare module 'vue' {
     readonly useAbs: UnwrapRef<typeof import('@vueuse/math')['useAbs']>
     readonly useActiveElement: UnwrapRef<typeof import('@vueuse/core')['useActiveElement']>
     readonly useAnimate: UnwrapRef<typeof import('@vueuse/core')['useAnimate']>
-    readonly useApi: UnwrapRef<typeof import('./src/composables/useApi')['useApi']>
     readonly useArrayDifference: UnwrapRef<typeof import('@vueuse/core')['useArrayDifference']>
     readonly useArrayEvery: UnwrapRef<typeof import('@vueuse/core')['useArrayEvery']>
     readonly useArrayFilter: UnwrapRef<typeof import('@vueuse/core')['useArrayFilter']>