feat(vikon): move API token from .env to integration_credentials

- Rename VICON_TOKEN → VIKON_API_TOKEN in .env and config
- Add ViconApiToken service reading from integration_credentials table
- Update 3 Vicon services to use ViconApiToken instead of config()
- Config/env kept as fallback for clean migration

app/Services/Vicon/ViconApiToken.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Services\Vicon;
+
+use App\Containers\Dashboard\Tasks\IntegrationCredentials\GetIntegrationCredentialTask;
+
+class ViconApiToken
+{
+    public function __construct(
+        private readonly GetIntegrationCredentialTask $getCredential,
+    ) {}
+
+    public function get(): string
+    {
+        $credential = $this->getCredential->run('vikon_api');
+
+        if (!$credential || empty($credential->payload['token'])) {
+            throw new \RuntimeException('VIKON API token not configured. Add it in /dashboard/integration-credentials.');
+        }
+
+        return $credential->payload['token'];
+    }
+}