feat(time-tracking) : add TimeEntry entity and migration

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

src/Repository/TimeEntryRepository.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Repository;
+
+use App\Entity\TimeEntry;
+use App\Entity\User;
+use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
+use Doctrine\Persistence\ManagerRegistry;
+
+/**
+ * @extends ServiceEntityRepository<TimeEntry>
+ */
+class TimeEntryRepository extends ServiceEntityRepository
+{
+    public function __construct(ManagerRegistry $registry)
+    {
+        parent::__construct($registry, TimeEntry::class);
+    }
+
+    public function findActiveByUser(User $user): ?TimeEntry
+    {
+        return $this->findOneBy([
+            'user'      => $user,
+            'stoppedAt' => null,
+        ]);
+    }
+}