chore: stage all in-progress work before repo split

Web app: new entities (Image, RenderedAsset, SharedImage, Token,
DeviceImageHistory), enums, repositories, controllers, message handlers,
migrations, tests, frontend upload/library/sticker UI, Vue components.

Firmware: EPD background screen binaries + gen scripts, setup_bg header.

Infra: ddev config, test bundle, gitignore coverage dir.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Message/RunImageCleanupMessage.php

@@ -0,0 +1,7 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Message;
+
+final class RunImageCleanupMessage {}