fix(scheduler): spread CDN update checks over a random delay

All instances share the same default update cron, so they request the
CDN at the same second and Cloudflare rejects the burst (error 1200).
Queue the CDN fetching jobs with a random 0-600s delay to spread the load.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/Feature/ScheduleOnOneServerTest.php

@@ -1,10 +1,16 @@
 <?php
 
+use App\Jobs\CheckForUpdatesJob;
+use App\Jobs\CheckHelperImageJob;
+use App\Jobs\PullChangelog;
+use App\Jobs\PullTemplatesFromCDN;
+use App\Jobs\UpdateCoolifyJob;
 use App\Models\InstanceSettings;
 use Illuminate\Console\Scheduling\Schedule;
 use Illuminate\Contracts\Console\Kernel;
 use Illuminate\Foundation\Testing\RefreshDatabase;
 use Illuminate\Support\Collection;
+use Illuminate\Support\Facades\Queue;
 
 uses(RefreshDatabase::class);
 
@@ -51,6 +57,22 @@ it('schedules every production job with onOneServer', function () {
     });
 });
 
+it('dispatches CDN fetching jobs with a random delay so instances do not hit the CDN at the same second', function () {
+    InstanceSettings::query()->whereKey(0)->update(['is_auto_update_enabled' => true]);
+    Queue::fake();
+
+    $jobs = [CheckHelperImageJob::class, CheckForUpdatesJob::class, PullTemplatesFromCDN::class, PullChangelog::class, UpdateCoolifyJob::class];
+    $schedule = app(Schedule::class);
+
+    foreach ($jobs as $job) {
+        $event = collect($schedule->events())->first(fn ($e) => $e->description === $job);
+        expect($event)->not->toBeNull("[{$job}] is not scheduled");
+        $event->run(app());
+
+        Queue::assertPushed($job, fn ($pushed) => is_int($pushed->delay) && $pushed->delay >= 0 && $pushed->delay <= 600);
+    }
+});
+
 it('does not schedule Stripe subscription reconciliation automatically', function () {
     $schedule = app(Schedule::class);