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.

tests/Feature/Server/HetznerServerPlaceholderIpTest.php

@@ -0,0 +1,118 @@
+<?php
+
+use App\Livewire\Server\New\ByHetzner;
+use App\Models\CloudProviderToken;
+use App\Models\InstanceSettings;
+use App\Models\PrivateKey;
+use App\Models\Server;
+use App\Models\Team;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Http;
+use Livewire\Livewire;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function () {
+    config([
+        'cache.default' => 'array',
+        'session.driver' => 'array',
+    ]);
+
+    InstanceSettings::unguarded(fn () => InstanceSettings::query()->create([
+        'id' => 0,
+    ]));
+
+    $this->team = Team::factory()->create();
+    $this->user = User::factory()->create();
+    $this->team->members()->attach($this->user->id, ['role' => 'owner']);
+
+    $this->actingAs($this->user);
+    session(['currentTeam' => $this->team]);
+
+    $this->hetznerToken = CloudProviderToken::create([
+        'team_id' => $this->team->id,
+        'provider' => 'hetzner',
+        'token' => 'test-hetzner-token',
+        'name' => 'Test Hetzner Token',
+    ]);
+
+    $this->privateKey = PrivateKey::factory()->create(['team_id' => $this->team->id]);
+});
+
+it('persists the server with a placeholder IP when Hetzner has not assigned one yet', function () {
+    Http::fake([
+        'https://api.hetzner.cloud/v1/ssh_keys' => Http::response([
+            'ssh_key' => ['id' => 42, 'fingerprint' => 'ff:ff'],
+        ], 201),
+        'https://api.hetzner.cloud/v1/ssh_keys*' => Http::response([
+            'ssh_keys' => [],
+        ], 200),
+        'https://api.hetzner.cloud/v1/servers' => Http::response([
+            'server' => [
+                'id' => 777,
+                'status' => 'initializing',
+                'public_net' => [
+                    'ipv4' => null,
+                    'ipv6' => null,
+                ],
+            ],
+        ], 201),
+    ]);
+
+    Livewire::test(ByHetzner::class, ['selectedTokenUuid' => $this->hetznerToken->uuid])
+        ->assertSet('current_step', 2)
+        ->set('server_name', 'test-hetzner-server')
+        ->set('selected_location', 'fsn1')
+        ->set('selected_server_type', 'cx22')
+        ->set('selected_image', 114690387)
+        ->set('private_key_id', $this->privateKey->id)
+        ->call('submit')
+        ->assertHasNoErrors();
+
+    $this->assertDatabaseHas('servers', [
+        'name' => 'test-hetzner-server',
+        'ip' => Server::PLACEHOLDER_IP,
+        'team_id' => $this->team->id,
+        'cloud_provider_token_id' => $this->hetznerToken->id,
+        'hetzner_server_id' => '777',
+        'hetzner_server_status' => 'initializing',
+    ]);
+});
+
+it('creates the server with the real IP when Hetzner assigns one immediately', function () {
+    Http::fake([
+        'https://api.hetzner.cloud/v1/ssh_keys' => Http::response([
+            'ssh_key' => ['id' => 42, 'fingerprint' => 'ff:ff'],
+        ], 201),
+        'https://api.hetzner.cloud/v1/ssh_keys*' => Http::response([
+            'ssh_keys' => [],
+        ], 200),
+        'https://api.hetzner.cloud/v1/servers' => Http::response([
+            'server' => [
+                'id' => 777,
+                'status' => 'running',
+                'public_net' => [
+                    'ipv4' => ['ip' => '203.0.113.30'],
+                ],
+            ],
+        ], 201),
+    ]);
+
+    Livewire::test(ByHetzner::class, ['selectedTokenUuid' => $this->hetznerToken->uuid])
+        ->assertSet('current_step', 2)
+        ->set('server_name', 'test-hetzner-server')
+        ->set('selected_location', 'fsn1')
+        ->set('selected_server_type', 'cx22')
+        ->set('selected_image', 114690387)
+        ->set('private_key_id', $this->privateKey->id)
+        ->call('submit')
+        ->assertHasNoErrors();
+
+    $this->assertDatabaseHas('servers', [
+        'name' => 'test-hetzner-server',
+        'ip' => '203.0.113.30',
+        'hetzner_server_id' => '777',
+        'hetzner_server_status' => 'running',
+    ]);
+});