fix(destinations): handle empty and server-scoped destinations

Build the global destinations list from actual destination records so empty
servers do not render duplicate empty states. Allow creating Docker destinations
for a selected team server outside the global usable list, authorize swarm
creation correctly, and store discovered swarm network names from the selected
network. Add feature coverage for empty states, selected-server mounting, and
swarm destination creation.

app/Livewire/Destination/Index.php

@@ -3,6 +3,7 @@
 namespace App\Livewire\Destination;
 
 use App\Models\Server;
+use Illuminate\Support\Collection;
 use Livewire\Attributes\Locked;
 use Livewire\Component;
 
@@ -11,9 +12,15 @@ class Index extends Component
     #[Locked]
     public $servers;
 
-    public function mount()
+    #[Locked]
+    public Collection $destinations;
+
+    public function mount(): void
     {
         $this->servers = Server::isUsable()->get();
+        $this->destinations = $this->servers
+            ->flatMap(fn (Server $server) => $server->standaloneDockers->concat($server->swarmDockers))
+            ->values();
     }
 
     public function render()