refactor: show organisation slug after name in header

Display the organisation slug in small muted text directly after the
organisation name on both the organizer page (/organisation) and the
platform admin detail page (/platform/organisations/[id]).

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

apps/app/src/pages/organisation/index.vue

@@ -225,6 +225,7 @@ function confirmRevokeInvitation() {
         <div class="d-flex align-center gap-x-3">
           <h4 class="text-h4">
             {{ organisation.name }}
+            <span class="text-body-2 text-medium-emphasis font-weight-regular ms-2">{{ organisation.slug }}</span>
           </h4>
           <VChip
             :color="statusColor[organisation.billing_status]"

apps/app/src/pages/platform/organisations/[id].vue

@@ -246,6 +246,7 @@ function formatDate(iso: string): string {
             <div class="d-flex align-center gap-x-2">
               <h4 class="text-h4">
                 {{ org.name }}
+                <span class="text-body-2 text-medium-emphasis font-weight-regular ms-2">{{ org.slug }}</span>
               </h4>
               <VChip
                 :color="billingStatusColor[org.billing_status]"
@@ -255,8 +256,7 @@ function formatDate(iso: string): string {
               </VChip>
             </div>
             <span class="text-caption text-medium-emphasis">
-              {{ org.slug }}
-              &middot; Aangemaakt op {{ formatDate(org.created_at) }}
+              Aangemaakt op {{ formatDate(org.created_at) }}
               &middot; Gewijzigd op {{ formatDate(org.updated_at) }}
             </span>
           </div>