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>

migrations/Version20260506000000.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20260506000000 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add device_image_history table for rotation uniqueness tracking';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('CREATE TABLE device_image_history (
+            id SERIAL NOT NULL,
+            device_id INT NOT NULL,
+            image_id INT NOT NULL,
+            served_at TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL,
+            PRIMARY KEY(id)
+        )');
+        $this->addSql('CREATE INDEX idx_history_device_served ON device_image_history (device_id, served_at)');
+        $this->addSql('ALTER TABLE device_image_history ADD CONSTRAINT fk_history_device FOREIGN KEY (device_id) REFERENCES device (id) ON DELETE CASCADE NOT DEFERRABLE INITIALLY IMMEDIATE');
+        $this->addSql('ALTER TABLE device_image_history ADD CONSTRAINT fk_history_image FOREIGN KEY (image_id) REFERENCES image (id) ON DELETE CASCADE NOT DEFERRABLE INITIALLY IMMEDIATE');
+        $this->addSql('COMMENT ON COLUMN device_image_history.served_at IS \'(DC2Type:datetime_immutable)\'');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE device_image_history DROP CONSTRAINT fk_history_device');
+        $this->addSql('ALTER TABLE device_image_history DROP CONSTRAINT fk_history_image');
+        $this->addSql('DROP TABLE device_image_history');
+    }
+}