refactor(scheduled-task): simplify server() with nullsafe operators and add return type

Replace nested null checks with nullsafe operator chains, add ?Server
return type, drop unreachable database branch, and cover all paths with
feature tests.

app/Models/ScheduledTask.php

@@ -76,20 +76,14 @@ class ScheduledTask extends BaseModel
         return $this->hasMany(ScheduledTaskExecution::class)->orderBy('created_at', 'desc');
     }
 
-    public function server()
+    public function server(): ?Server
     {
         if ($this->application) {
-            if ($this->application->destination && $this->application->destination->server) {
-                return $this->application->destination->server;
-            }
-        } elseif ($this->service) {
-            if ($this->service->destination && $this->service->destination->server) {
-                return $this->service->destination->server;
-            }
-        } elseif ($this->database) {
-            if ($this->database->destination && $this->database->destination->server) {
-                return $this->database->destination->server;
-            }
+            return $this->application->destination?->server;
+        }
+
+        if ($this->service) {
+            return $this->service->destination?->server;
         }
 
         return null;

tests/Feature/ScheduledTaskServerTest.php

@@ -0,0 +1,66 @@
+<?php
+
+use App\Models\Application;
+use App\Models\Project;
+use App\Models\ScheduledTask;
+use App\Models\Server;
+use App\Models\Service;
+use App\Models\StandaloneDocker;
+use App\Models\Team;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function () {
+    $this->team = Team::factory()->create();
+    $this->server = Server::factory()->create(['team_id' => $this->team->id]);
+    $this->destination = StandaloneDocker::where('server_id', $this->server->id)->first();
+    $this->project = Project::factory()->create(['team_id' => $this->team->id]);
+    $this->environment = $this->project->environments()->first();
+});
+
+it('returns null when neither application nor service is set', function () {
+    $task = ScheduledTask::factory()->create([
+        'team_id' => $this->team->id,
+    ]);
+
+    expect($task->server())->toBeNull();
+});
+
+it('does not throw when accessing dynamic properties on a parentless task', function () {
+    $task = ScheduledTask::factory()->create([
+        'team_id' => $this->team->id,
+    ]);
+
+    expect(fn () => $task->server())->not->toThrow(Exception::class);
+});
+
+it('resolves server via application destination', function () {
+    $application = Application::factory()->create([
+        'environment_id' => $this->environment->id,
+        'destination_id' => $this->destination->id,
+        'destination_type' => $this->destination->getMorphClass(),
+    ]);
+
+    $task = ScheduledTask::factory()->create([
+        'application_id' => $application->id,
+        'team_id' => $this->team->id,
+    ]);
+
+    expect($task->server()?->id)->toBe($this->server->id);
+});
+
+it('resolves server via service destination', function () {
+    $service = Service::factory()->create([
+        'environment_id' => $this->environment->id,
+        'destination_id' => $this->destination->id,
+        'destination_type' => $this->destination->getMorphClass(),
+    ]);
+
+    $task = ScheduledTask::factory()->create([
+        'service_id' => $service->id,
+        'team_id' => $this->team->id,
+    ]);
+
+    expect($task->server()?->id)->toBe($this->server->id);
+});