refactor: run emoji cloud migration as a queued job, not inline in migrate

Running the ~25k-file S3 upload synchronously via Artisan::call inside the
migration blocked the upgrade with no visible output, and a mid-run failure
would leave the migration in a bad state.

Dispatch EmojiMigrateToCloudPipeline (ShouldQueue, ShouldBeUnique) onto the
mmo queue instead, so migrate returns immediately and the upload runs in the
background on Horizon. The job re-checks the cloud-storage guard at runtime,
runs the async command (--concurrency=100), has a 1h timeout and tries=1,
and is unique so it can't stack up.

app/Jobs/MediaPipeline/EmojiMigrateToCloudPipeline.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace App\Jobs\MediaPipeline;
+
+use Illuminate\Bus\Queueable;
+use Illuminate\Contracts\Queue\ShouldBeUnique;
+use Illuminate\Contracts\Queue\ShouldQueue;
+use Illuminate\Foundation\Bus\Dispatchable;
+use Illuminate\Queue\InteractsWithQueue;
+use Illuminate\Queue\SerializesModels;
+use Illuminate\Support\Facades\Artisan;
+use Illuminate\Support\Facades\Log;
+
+class EmojiMigrateToCloudPipeline implements ShouldBeUnique, ShouldQueue
+{
+    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;
+
+    /**
+     * Bulk emoji upload can take a while; allow up to an hour.
+     */
+    public $timeout = 3600;
+
+    /**
+     * Do not auto-retry a long bulk transfer. It is safe to re-dispatch
+     * manually, but automatic retries would re-run the whole upload.
+     */
+    public $tries = 1;
+
+    /**
+     * Only one migration job should be queued/running at a time.
+     */
+    public $uniqueFor = 3600;
+
+    public function uniqueId(): string
+    {
+        return 'emoji-migrate-to-cloud';
+    }
+
+    public function handle(): void
+    {
+        // Guard again at run time in case cloud storage was toggled off between
+        // dispatch and execution.
+        $cloudEnabled = (bool) config('pixelfed.cloud_storage') || (bool) config_cache('pixelfed.cloud_storage');
+
+        if (! $cloudEnabled) {
+            Log::info('EmojiMigrateToCloudPipeline: cloud storage not enabled, skipping.');
+
+            return;
+        }
+
+        Log::info('EmojiMigrateToCloudPipeline: starting emoji migration to cloud.');
+
+        Artisan::call('admin:EmojiMoveStorageLocalToCloud', [
+            '--force' => true,
+            '--concurrency' => 100,
+        ]);
+
+        Log::info('EmojiMigrateToCloudPipeline: finished. '.trim(Artisan::output()));
+    }
+}

database/migrations/2026_08_30_050000_migrate_local_emoji_to_cloud.php

@@ -1,7 +1,7 @@
 <?php
 
+use App\Jobs\MediaPipeline\EmojiMigrateToCloudPipeline;
 use Illuminate\Database\Migrations\Migration;
-use Illuminate\Support\Facades\Artisan;
 
 return new class extends Migration
 {
@@ -9,23 +9,24 @@ return new class extends Migration
      * Run the migrations.
      *
      * When cloud storage is enabled, custom emoji URLs resolve to the cloud
-     * disk. Existing emoji may still only exist locally, so move them all to
-     * cloud now (in one pass) to avoid a window where their URLs 404. This is
-     * a no-op on local-only instances.
+     * disk. Existing emoji may still only exist locally, so migrate them to
+     * cloud to avoid a window where their URLs 404.
+     *
+     * The upload is potentially large and network-bound, so we dispatch it to
+     * the queue and return immediately rather than blocking the upgrade. The
+     * work runs in the background on Horizon. No-op on local-only instances.
      */
     public function up(): void
     {
         // Consider cloud enabled if either the live config or the (possibly
-        // cached) config_cache value says so; the command guards again anyway.
+        // cached) config_cache value says so; the job guards again at runtime.
         $cloudEnabled = (bool) config('pixelfed.cloud_storage') || (bool) config_cache('pixelfed.cloud_storage');
 
         if (! $cloudEnabled) {
             return;
         }
 
-        Artisan::call('admin:EmojiMoveStorageLocalToCloud', [
-            '--force' => true,
-        ]);
+        EmojiMigrateToCloudPipeline::dispatch()->onQueue('mmo');
     }
 
     /**