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>

tests/Unit/Repository/UserRepositoryTest.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Repository;
+
+use App\Entity\User;
+use App\Repository\UserRepository;
+use App\Tests\AppKernelTestCase;
+use Symfony\Component\Security\Core\Exception\UnsupportedUserException;
+use Symfony\Component\Security\Core\User\PasswordAuthenticatedUserInterface;
+
+class UserRepositoryTest extends AppKernelTestCase
+{
+    private UserRepository $repo;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->repo = static::getContainer()->get(UserRepository::class);
+    }
+
+    // UR-01: valid User → password updated in DB
+    public function test_upgrade_password_updates_password_for_valid_user(): void
+    {
+        $user = $this->createUser('ur01@example.com', 'oldpassword');
+        $userId = $user->getId();
+
+        $this->repo->upgradePassword($user, 'newhashed_password');
+
+        $this->em()->clear();
+        $reloaded = $this->em()->find(User::class, $userId);
+        $this->assertSame('newhashed_password', $reloaded->getPassword());
+    }
+
+    // UR-02: non-User PasswordAuthenticatedUserInterface → throws UnsupportedUserException
+    public function test_upgrade_password_throws_for_non_user(): void
+    {
+        $fakeUser = new class implements PasswordAuthenticatedUserInterface {
+            public function getPassword(): ?string { return null; }
+            public function getUserIdentifier(): string { return 'fake'; }
+            public function getRoles(): array { return []; }
+            public function eraseCredentials(): void {}
+        };
+
+        $this->expectException(UnsupportedUserException::class);
+        $this->repo->upgradePassword($fakeUser, 'newpassword');
+    }
+}