fix(queue): route cloud jobs to dedicated queues

Use config-based queue selection for deployment and scheduled jobs so cloud dispatches deployments to `deployments` and scheduled jobs to `crons`, while self-hosted keeps using `high`.

Add coverage for deployment queue helper, start action routing, and scheduled job manager routing.

app/Jobs/ApplicationDeploymentJob.php

@@ -197,7 +197,7 @@ class ApplicationDeploymentJob implements ShouldBeEncrypted, ShouldQueue
 
     public function __construct(public int $application_deployment_queue_id)
     {
-        $this->onQueue('high');
+        $this->onQueue(deployment_queue());
 
         $this->application_deployment_queue = ApplicationDeploymentQueue::find($this->application_deployment_queue_id);
         $this->nixpacks_plan_json = collect([]);