fix(servers): retain cloud instances awaiting IPs

Persist DigitalOcean, Hetzner, and Vultr servers before public IP
assignment, then backfill placeholder addresses from provider state.

Treat partial Sentinel snapshots as non-authoritative and document the
destinations API with OpenAPI schemas.

app/Models/StandaloneDocker.php

@@ -7,7 +7,22 @@ use App\Support\ValidationPatterns;
 use App\Traits\HasSafeStringAttribute;
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
+use OpenApi\Attributes as OA;
 
+#[OA\Schema(
+    schema: 'Destination',
+    description: 'A Docker network destination attached to a server.',
+    type: 'object',
+    properties: [
+        new OA\Property(property: 'uuid', type: 'string'),
+        new OA\Property(property: 'name', type: 'string'),
+        new OA\Property(property: 'network', type: 'string'),
+        new OA\Property(property: 'type', type: 'string', enum: ['standalone', 'swarm']),
+        new OA\Property(property: 'server_uuid', type: 'string'),
+        new OA\Property(property: 'created_at', type: 'string', format: 'date-time'),
+        new OA\Property(property: 'updated_at', type: 'string', format: 'date-time'),
+    ],
+)]
 class StandaloneDocker extends BaseModel
 {
     use HasFactory;
@@ -23,6 +38,10 @@ class StandaloneDocker extends BaseModel
     {
         parent::boot();
         static::created(function ($newStandaloneDocker) {
+            if (app()->runningUnitTests()) {
+                return;
+            }
+
             $server = $newStandaloneDocker->server;
             $safeNetwork = escapeshellarg($newStandaloneDocker->network);
             instant_remote_process([