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/Version20260507200000.php

@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20260507200000 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add shared_image table for family sharing';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql("CREATE TABLE shared_image (
+            id SERIAL NOT NULL,
+            source_image_id INT NOT NULL,
+            recipient_user_id INT NOT NULL,
+            shared_by_id INT NOT NULL,
+            shared_at TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL,
+            status VARCHAR(20) NOT NULL DEFAULT 'pending',
+            PRIMARY KEY(id)
+        )");
+        $this->addSql("COMMENT ON COLUMN shared_image.shared_at IS '(DC2Type:datetime_immutable)'");
+        $this->addSql('CREATE INDEX idx_shared_recipient_status ON shared_image (recipient_user_id, status)');
+        $this->addSql('ALTER TABLE shared_image ADD CONSTRAINT fk_shared_source FOREIGN KEY (source_image_id) REFERENCES image (id) ON DELETE CASCADE NOT DEFERRABLE INITIALLY IMMEDIATE');
+        $this->addSql('ALTER TABLE shared_image ADD CONSTRAINT fk_shared_recipient FOREIGN KEY (recipient_user_id) REFERENCES "user" (id) ON DELETE CASCADE NOT DEFERRABLE INITIALLY IMMEDIATE');
+        $this->addSql('ALTER TABLE shared_image ADD CONSTRAINT fk_shared_by FOREIGN KEY (shared_by_id) REFERENCES "user" (id) ON DELETE CASCADE NOT DEFERRABLE INITIALLY IMMEDIATE');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE shared_image DROP CONSTRAINT fk_shared_source');
+        $this->addSql('ALTER TABLE shared_image DROP CONSTRAINT fk_shared_recipient');
+        $this->addSql('ALTER TABLE shared_image DROP CONSTRAINT fk_shared_by');
+        $this->addSql('DROP TABLE shared_image');
+    }
+}