fix(vultr): validate public network and token scope

Require IPv6 when public IPv4 is disabled, constrain cloud token
lookup by team and provider during deletion, and encode Vultr instance IDs
in API paths.

tests/Unit/VultrServiceTest.php

@@ -150,3 +150,17 @@ it('handles empty successful responses from Vultr API', function () {
 
     Http::assertSentCount(2);
 });
+
+it('encodes instance IDs in request paths', function () {
+    Http::fake([
+        'https://api.vultr.com/v2/instances/instance%2F1' => Http::response([
+            'instance' => ['id' => 'instance/1'],
+        ], 200),
+    ]);
+
+    $service = new VultrService('fake-token');
+
+    expect($service->getInstance('instance/1')['id'])->toBe('instance/1');
+
+    Http::assertSent(fn ($request) => $request->url() === 'https://api.vultr.com/v2/instances/instance%2F1');
+});