feat: registration field polish, multi-category tags, file uploads, Partner icon

- Restructure field editor dialog: move Options section to bottom with
  divider and subheader, fix delete button with flex layout
- Change tag_category (single string) to tag_categories (JSON array)
  supporting multiple category selection in tag picker fields
- Portal tag picker now groups tags by category with subheaders
- Add generic file upload endpoint (FileUploadService + UploadController)
- Replace email branding logo URL text field with ImageUploadField
- Update Partner crowd type default icon to tabler-affiliate
- Apply changes consistently to both field and template dialogs

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

api/tests/Feature/Api/V1/PublicRegistrationDataTest.php

@@ -317,7 +317,7 @@ class PublicRegistrationDataTest extends TestCase
 
         RegistrationFormField::factory()->tagPickerField()->create([
             'event_id' => $event->id,
-            'tag_category' => 'Certificaat',
+            'tag_categories' => ['Certificaat'],
             'is_portal_visible' => true,
             'is_admin_only' => false,
         ]);

api/tests/Feature/Api/V1/UploadTest.php

@@ -0,0 +1,125 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Feature\Api\V1;
+
+use App\Models\Organisation;
+use App\Models\User;
+use Database\Seeders\RoleSeeder;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Http\UploadedFile;
+use Illuminate\Support\Facades\Storage;
+use Laravel\Sanctum\Sanctum;
+use Tests\TestCase;
+
+class UploadTest extends TestCase
+{
+    use RefreshDatabase;
+
+    private User $user;
+    private Organisation $organisation;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->seed(RoleSeeder::class);
+
+        $this->organisation = Organisation::factory()->create();
+        $this->user = User::factory()->create();
+        $this->organisation->users()->attach($this->user, ['role' => 'org_admin']);
+
+        Storage::fake('public');
+    }
+
+    public function test_upload_image_succeeds_with_valid_png(): void
+    {
+        Sanctum::actingAs($this->user);
+
+        $file = UploadedFile::fake()->image('logo.png', 200, 200);
+
+        $response = $this->postJson('/api/v1/upload/image', [
+            'file' => $file,
+            'purpose' => 'logo',
+        ]);
+
+        $response->assertOk()
+            ->assertJsonStructure(['data' => ['url']]);
+
+        $url = $response->json('data.url');
+        $this->assertStringContainsString('uploads/logo', $url);
+    }
+
+    public function test_upload_image_rejects_unsupported_mime(): void
+    {
+        Sanctum::actingAs($this->user);
+
+        $file = UploadedFile::fake()->create('document.pdf', 100, 'application/pdf');
+
+        $response = $this->postJson('/api/v1/upload/image', [
+            'file' => $file,
+            'purpose' => 'logo',
+        ]);
+
+        $response->assertStatus(422);
+    }
+
+    public function test_upload_image_rejects_oversized_file(): void
+    {
+        Sanctum::actingAs($this->user);
+
+        $file = UploadedFile::fake()->image('large.png')->size(6000); // 6MB > 5MB limit
+
+        $response = $this->postJson('/api/v1/upload/image', [
+            'file' => $file,
+            'purpose' => 'logo',
+        ]);
+
+        $response->assertStatus(422);
+    }
+
+    public function test_upload_image_requires_authentication(): void
+    {
+        $file = UploadedFile::fake()->image('logo.png', 200, 200);
+
+        $response = $this->postJson('/api/v1/upload/image', [
+            'file' => $file,
+            'purpose' => 'logo',
+        ]);
+
+        $response->assertUnauthorized();
+    }
+
+    public function test_upload_image_logs_activity(): void
+    {
+        Sanctum::actingAs($this->user);
+
+        $file = UploadedFile::fake()->image('logo.png', 200, 200);
+
+        $this->postJson('/api/v1/upload/image', [
+            'file' => $file,
+            'purpose' => 'logo',
+        ]);
+
+        $this->assertDatabaseHas('activity_log', [
+            'log_name' => 'upload',
+            'description' => 'image.uploaded',
+            'causer_id' => $this->user->id,
+        ]);
+    }
+
+    public function test_upload_image_requires_valid_purpose(): void
+    {
+        Sanctum::actingAs($this->user);
+
+        $file = UploadedFile::fake()->image('logo.png', 200, 200);
+
+        $response = $this->postJson('/api/v1/upload/image', [
+            'file' => $file,
+            'purpose' => 'invalid',
+        ]);
+
+        $response->assertUnprocessable()
+            ->assertJsonValidationErrors('purpose');
+    }
+}

api/tests/Feature/RegistrationFormField/RegistrationFormFieldTest.php

@@ -121,32 +121,32 @@ class RegistrationFormFieldTest extends TestCase
             ->assertJsonValidationErrors('options');
     }
 
-    public function test_store_tag_picker_accepts_tag_category(): void
+    public function test_store_tag_picker_accepts_tag_categories(): void
     {
         Sanctum::actingAs($this->orgAdmin);
 
         $response = $this->postJson("/api/v1/organisations/{$this->organisation->id}/events/{$this->event->id}/registration-fields", [
             'label' => 'Vaardigheden',
             'field_type' => 'tag_picker',
-            'tag_category' => 'Vaardigheid',
+            'tag_categories' => ['Vaardigheid', 'Horeca'],
         ]);
 
         $response->assertCreated()
-            ->assertJsonPath('data.tag_category', 'Vaardigheid');
+            ->assertJsonPath('data.tag_categories', ['Vaardigheid', 'Horeca']);
     }
 
-    public function test_store_text_field_rejects_tag_category(): void
+    public function test_store_text_field_rejects_tag_categories(): void
     {
         Sanctum::actingAs($this->orgAdmin);
 
         $response = $this->postJson("/api/v1/organisations/{$this->organisation->id}/events/{$this->event->id}/registration-fields", [
             'label' => 'Naam',
             'field_type' => 'text',
-            'tag_category' => 'Vaardigheid',
+            'tag_categories' => ['Vaardigheid'],
         ]);
 
         $response->assertUnprocessable()
-            ->assertJsonValidationErrors('tag_category');
+            ->assertJsonValidationErrors('tag_categories');
     }
 
     public function test_slug_uniqueness_per_event(): void