feat: add create organisation button and dialog on platform page

Add "Nieuwe organisatie" button to the platform organisations list page.
Dialog with name field (auto-generates slug) and slug field. Uses the
existing POST /organisations endpoint. On success, navigates to the
new organisation's detail page.

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

apps/app/src/composables/api/useAdmin.ts

@@ -7,6 +7,7 @@ import type {
   AdminOrganisationDetail,
   AdminOrganisationMember,
   AdminUser,
+  CreateOrganisationPayload,
   ImpersonationResponse,
   InviteMemberPayload,
   PlatformStats,
@@ -77,6 +78,23 @@ export function useUpdateAdminOrganisation() {
   })
 }
 
+export function useCreateOrganisation() {
+  const queryClient = useQueryClient()
+
+  return useMutation({
+    mutationFn: async (payload: CreateOrganisationPayload) => {
+      const { data } = await apiClient.post<ApiResponse<AdminOrganisation>>(
+        '/organisations',
+        payload,
+      )
+      return data.data
+    },
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['admin', 'organisations'] })
+    },
+  })
+}
+
 export function useDeleteAdminOrganisation() {
   const queryClient = useQueryClient()
 

apps/app/src/pages/platform/organisations/index.vue

@@ -1,6 +1,6 @@
 <script setup lang="ts">
-import { useAdminOrganisations } from '@/composables/api/useAdmin'
+import { useAdminOrganisations, useCreateOrganisation } from '@/composables/api/useAdmin'
-import type { AdminOrganisation, BillingStatus } from '@/types/admin'
+import type { AdminOrganisation, BillingStatus, CreateOrganisationPayload } from '@/types/admin'
 
 definePage({
   meta: {
@@ -76,6 +76,44 @@ function onUpdateOptions(options: { page: number; itemsPerPage: number; sortBy:
     sortDirection.value = options.sortBy[0].order as 'asc' | 'desc'
   }
 }
+
+// ─── Create organisation ────────────────────────────────────
+const isCreateDialogOpen = ref(false)
+const createForm = ref<CreateOrganisationPayload>({ name: '', slug: '' })
+const createError = ref('')
+const { mutate: createOrganisation, isPending: isCreating } = useCreateOrganisation()
+
+function slugify(text: string): string {
+  return text
+    .toLowerCase()
+    .replace(/[^a-z0-9]+/g, '-')
+    .replace(/^-+|-+$/g, '')
+}
+
+function openCreateDialog() {
+  createForm.value = { name: '', slug: '' }
+  createError.value = ''
+  isCreateDialogOpen.value = true
+}
+
+function onNameInput(name: string) {
+  createForm.value.name = name
+  createForm.value.slug = slugify(name)
+}
+
+function submitCreate() {
+  createError.value = ''
+  createOrganisation(createForm.value, {
+    onSuccess: (org) => {
+      isCreateDialogOpen.value = false
+      router.push({ name: 'platform-organisations-id', params: { id: org.id } })
+    },
+    onError: (err: unknown) => {
+      const error = err as { response?: { data?: { message?: string } } }
+      createError.value = error.response?.data?.message ?? 'Er is een fout opgetreden.'
+    },
+  })
+}
 </script>
 
 <template>
@@ -89,6 +127,12 @@ function onUpdateOptions(options: { page: number; itemsPerPage: number; sortBy:
           Alle organisaties op het platform
         </p>
       </div>
+      <VBtn
+        prepend-icon="tabler-plus"
+        @click="openCreateDialog"
+      >
+        Nieuwe organisatie
+      </VBtn>
     </div>
 
     <!-- Error -->
@@ -174,5 +218,58 @@ function onUpdateOptions(options: { page: number; itemsPerPage: number; sortBy:
         </template>
       </VDataTableServer>
     </VCard>
+
+    <!-- Create Dialog -->
+    <VDialog
+      v-model="isCreateDialogOpen"
+      max-width="500"
+    >
+      <VCard title="Nieuwe organisatie">
+        <VCardText>
+          <VAlert
+            v-if="createError"
+            type="error"
+            variant="tonal"
+            class="mb-4"
+            density="comfortable"
+          >
+            {{ createError }}
+          </VAlert>
+          <VRow>
+            <VCol cols="12">
+              <AppTextField
+                :model-value="createForm.name"
+                label="Naam"
+                @update:model-value="onNameInput"
+              />
+            </VCol>
+            <VCol cols="12">
+              <AppTextField
+                v-model="createForm.slug"
+                label="Slug"
+                hint="Wordt automatisch gegenereerd"
+              />
+            </VCol>
+          </VRow>
+        </VCardText>
+        <VCardActions>
+          <VSpacer />
+          <VBtn
+            variant="tonal"
+            @click="isCreateDialogOpen = false"
+          >
+            Annuleren
+          </VBtn>
+          <VBtn
+            color="primary"
+            :loading="isCreating"
+            :disabled="!createForm.name || !createForm.slug"
+            @click="submitCreate"
+          >
+            Aanmaken
+          </VBtn>
+        </VCardActions>
+      </VCard>
+    </VDialog>
   </div>
 </template>

apps/app/src/types/admin.ts

@@ -96,6 +96,12 @@ export interface UpdateMemberRolePayload {
   role: string
 }
 
+export interface CreateOrganisationPayload {
+  name: string
+  slug: string
+  billing_status?: BillingStatus
+}
+
 export interface UpdateAdminOrganisationPayload {
   name?: string
   slug?: string