feat(story-2.2+2.3): device setup page, account linking, naming & configuration

Story 2.2 — /setup/{mac} Twig page (no Vue, works JS-disabled):
- Register tab: creates account + logs in + links device → /setup/{mac}/configure
- Login tab: manual credential check via UserPasswordHasherInterface + Security::login()
  + links device → /setup/{mac}/configure
- Re-provisioning: DeviceService.linkToUser() atomically transfers ownership + stubs
  purgeDeviceHistory() (completed in Epic 3 when Image/Approval entities exist)

Story 2.3 — /setup/{mac}/configure (requires auth):
- GET: device name, orientation (landscape/portrait), rotation interval (6/12/24/48/168h),
  uniqueness window (5/10/20/50 cycles)
- POST: validates name, saves to Device entity, redirects to Vue SPA
- Device entity: mac, name, orientation (Orientation enum), rotationIntervalHours,
  uniquenessWindow, user (ManyToOne), linkedAt
- PATCH /api/devices/{id}: Vue SPA can edit any device field (Story 2.3 "edit from app")
- GET /api/devices: list authenticated user's devices
- Migration: create device table with Orientation enum column

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

src/Service/DeviceService.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\Entity\Device;
+use App\Entity\User;
+use App\Repository\DeviceRepository;
+use Doctrine\ORM\EntityManagerInterface;
+
+class DeviceService
+{
+    public function __construct(
+        private readonly DeviceRepository $repo,
+        private readonly EntityManagerInterface $em,
+    ) {}
+
+    /**
+     * Atomically link a MAC address to a user.
+     * If the device was previously owned by a different user, image history is purged.
+     */
+    public function linkToUser(string $mac, User $newOwner): Device
+    {
+        $mac = strtoupper($mac);
+        $device = $this->repo->findOneBy(['mac' => $mac]);
+
+        if ($device === null) {
+            $device = new Device();
+            $device->setMac($mac);
+        } elseif ($device->getUser() !== null && $device->getUser()->getId() !== $newOwner->getId()) {
+            // Ownership transfer: purge prior image history for this device.
+            // Full purge logic added in Epic 3 when Image/Approval entities exist.
+            $this->purgeDeviceHistory($device);
+        }
+
+        $device->setUser($newOwner);
+        $device->setLinkedAt(new \DateTimeImmutable());
+        $this->em->persist($device);
+        $this->em->flush();
+
+        return $device;
+    }
+
+    /** Remove all image approvals and rendered assets associated with this device. */
+    private function purgeDeviceHistory(Device $device): void
+    {
+        // Stub: will cascade-delete via ORM relationships once Image/Approval entities are added in Epic 3.
+        // Doctrine cascade on the Device→Approval relationship handles this automatically.
+    }
+}