feat: show identity match hint on registration success page

When a pending identity match is detected after volunteer registration,
the API now returns has_existing_account in the response. The success
page shows a login suggestion card so the volunteer can link their
registration to their existing account.

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

api/app/Http/Controllers/Api/V1/VolunteerRegistrationController.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Controllers\Api\V1;
+
+use App\Enums\IdentityMatchStatus;
+use App\Http\Controllers\Controller;
+use App\Http\Requests\Api\V1\VolunteerRegistrationRequest;
+use App\Http\Resources\Api\V1\PersonResource;
+use App\Models\Event;
+use App\Models\PersonIdentityMatch;
+use App\Services\VolunteerRegistrationService;
+use Illuminate\Http\JsonResponse;
+
+final class VolunteerRegistrationController extends Controller
+{
+    public function __construct(
+        private readonly VolunteerRegistrationService $registrationService,
+    ) {}
+
+    public function __invoke(VolunteerRegistrationRequest $request, Event $event): JsonResponse
+    {
+        $user = auth('sanctum')->user();
+
+        $person = $this->registrationService->register(
+            $event,
+            $request->validated(),
+            $user
+        );
+
+        $person->load('crowdType');
+
+        $hasExistingAccount = PersonIdentityMatch::where('person_id', $person->id)
+            ->where('status', IdentityMatchStatus::PENDING)
+            ->exists();
+
+        $responseData = [
+            'person' => new PersonResource($person),
+            'has_existing_account' => $hasExistingAccount,
+        ];
+
+        if ($person->wasRecentlyCreated) {
+            return $this->created($responseData);
+        }
+
+        return $this->success($responseData);
+    }
+}

apps/portal/src/composables/api/useVolunteerRegistration.ts

@@ -22,10 +22,15 @@ export function useRegistrationData(eventSlug: Ref<string>) {
   })
 }
 
+export interface VolunteerRegistrationResponse {
+  person: Record<string, unknown>
+  has_existing_account: boolean
+}
+
 export function useSubmitRegistration() {
   return useMutation({
     mutationFn: async ({ eventId, form }: { eventId: string; form: VolunteerRegistrationForm }) => {
-      const { data } = await apiClient.post<ApiResponse<Record<string, unknown>>>(
+      const { data } = await apiClient.post<ApiResponse<VolunteerRegistrationResponse>>(
         `/events/${eventId}/volunteer-register`,
         form,
       )

apps/portal/src/pages/register/[eventSlug].vue

@@ -622,7 +622,7 @@ async function onSubmit() {
   if (section_preferences?.length) payload.section_preferences = section_preferences
 
   try {
-    await submitRegistration({
+    const result = await submitRegistration({
       eventId: registrationData.value.event.id,
       form: payload,
     })
@@ -644,6 +644,7 @@ async function onSubmit() {
         event: registrationData.value.event.name,
         banner: registrationData.value.event.registration_banner_url ?? '',
         authenticated: authStore.isAuthenticated ? '1' : '0',
+        hasAccount: result.has_existing_account ? '1' : '0',
       },
     })
   }

apps/portal/src/pages/register/success.vue

@@ -16,6 +16,7 @@ const authStore = useAuthStore()
 const eventName = computed(() => (route.query.event as string) || 'het evenement')
 const bannerUrl = computed(() => (route.query.banner as string) || null)
 const isAuthenticated = computed(() => route.query.authenticated === '1' || authStore.isAuthenticated)
+const hasExistingAccount = computed(() => route.query.hasAccount === '1' && !isAuthenticated.value)
 </script>
 
 <template>
@@ -102,6 +103,35 @@ const isAuthenticated = computed(() => route.query.authenticated === '1' || auth
         </div>
       </VCard>
 
+      <VAlert
+        v-if="hasExistingAccount"
+        type="info"
+        variant="tonal"
+        class="mt-4"
+      >
+        <div class="font-weight-medium mb-1">
+          Er bestaat al een account met dit e-mailadres
+        </div>
+        <p class="text-body-2 mb-3">
+          Log in om je aanmelding te koppelen aan je bestaande account.
+          Zo kun je straks je diensten bekijken in het portaal.
+        </p>
+        <VBtn
+          size="small"
+          color="primary"
+          variant="flat"
+          :to="{ name: 'login' }"
+        >
+          <VIcon
+            start
+            size="16"
+          >
+            tabler-login
+          </VIcon>
+          Inloggen
+        </VBtn>
+      </VAlert>
+
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