Free app_name on failure too, not just on delete

Failed provisioning now appends '-failed-{timestamp}' to app_name,
freeing it for retry without manual cleanup.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Services/InstanceProvisionerService.php

@@ -53,6 +53,7 @@ public function provision(Client $client, Plan $plan, array $data, ?callable $on
         } catch (\Throwable $e) {
             $instance->update([
                 'status' => 'failed',
+                'app_name' => $instance->app_name . '-failed-' . now()->timestamp,
                 'caprover_deploy_log' => $e->getMessage(),
             ]);
             throw new RuntimeException("Provisioning failed: {$e->getMessage()}", 0, $e);