feat: Permettre la création et modification de l'emploi du temps des classes

L'administration a besoin de construire et maintenir les emplois du temps
hebdomadaires pour chaque classe, en s'assurant que les enseignants ne sont
pas en conflit (même créneau, classes différentes) et que les affectations
enseignant-matière-classe sont respectées.

Cette implémentation couvre le CRUD complet des créneaux (ScheduleSlot),
la détection de conflits (classe, enseignant, salle) avec possibilité de
forcer, la validation des affectations côté serveur (AC2), l'intégration
calendrier pour les jours bloqués, une vue mobile-first avec onglets jour
par jour, et le drag-and-drop pour réorganiser les créneaux sur desktop.

backend/tests/Unit/Scolarite/Domain/Model/Schedule/TimeSlotTest.php

@@ -0,0 +1,120 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Unit\Scolarite\Domain\Model\Schedule;
+
+use App\Scolarite\Domain\Exception\CreneauHoraireInvalideException;
+use App\Scolarite\Domain\Model\Schedule\TimeSlot;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class TimeSlotTest extends TestCase
+{
+    #[Test]
+    public function createsValidTimeSlot(): void
+    {
+        $timeSlot = new TimeSlot('08:00', '09:00');
+
+        self::assertSame('08:00', $timeSlot->startTime);
+        self::assertSame('09:00', $timeSlot->endTime);
+    }
+
+    #[Test]
+    public function throwsWhenEndTimeBeforeStartTime(): void
+    {
+        $this->expectException(CreneauHoraireInvalideException::class);
+
+        new TimeSlot('10:00', '09:00');
+    }
+
+    #[Test]
+    public function throwsWhenEndTimeEqualsStartTime(): void
+    {
+        $this->expectException(CreneauHoraireInvalideException::class);
+
+        new TimeSlot('08:00', '08:00');
+    }
+
+    #[Test]
+    public function throwsWhenDurationLessThanFiveMinutes(): void
+    {
+        $this->expectException(CreneauHoraireInvalideException::class);
+
+        new TimeSlot('08:00', '08:04');
+    }
+
+    #[Test]
+    public function acceptsFiveMinuteDuration(): void
+    {
+        $timeSlot = new TimeSlot('08:00', '08:05');
+
+        self::assertSame('08:00', $timeSlot->startTime);
+        self::assertSame('08:05', $timeSlot->endTime);
+    }
+
+    #[Test]
+    public function overlapsReturnsTrueWhenTimesOverlap(): void
+    {
+        $slot1 = new TimeSlot('08:00', '09:00');
+        $slot2 = new TimeSlot('08:30', '09:30');
+
+        self::assertTrue($slot1->overlaps($slot2));
+        self::assertTrue($slot2->overlaps($slot1));
+    }
+
+    #[Test]
+    public function overlapsReturnsFalseWhenTimesDoNotOverlap(): void
+    {
+        $slot1 = new TimeSlot('08:00', '09:00');
+        $slot2 = new TimeSlot('09:00', '10:00');
+
+        self::assertFalse($slot1->overlaps($slot2));
+        self::assertFalse($slot2->overlaps($slot1));
+    }
+
+    #[Test]
+    public function overlapsReturnsTrueWhenOneContainsOther(): void
+    {
+        $slot1 = new TimeSlot('08:00', '12:00');
+        $slot2 = new TimeSlot('09:00', '10:00');
+
+        self::assertTrue($slot1->overlaps($slot2));
+        self::assertTrue($slot2->overlaps($slot1));
+    }
+
+    #[Test]
+    public function overlapsReturnsFalseWhenAdjacent(): void
+    {
+        $slot1 = new TimeSlot('08:00', '09:00');
+        $slot2 = new TimeSlot('09:00', '10:00');
+
+        self::assertFalse($slot1->overlaps($slot2));
+    }
+
+    #[Test]
+    public function equalsReturnsTrueForSameTimes(): void
+    {
+        $slot1 = new TimeSlot('08:00', '09:00');
+        $slot2 = new TimeSlot('08:00', '09:00');
+
+        self::assertTrue($slot1->equals($slot2));
+    }
+
+    #[Test]
+    public function equalsReturnsFalseForDifferentTimes(): void
+    {
+        $slot1 = new TimeSlot('08:00', '09:00');
+        $slot2 = new TimeSlot('08:00', '10:00');
+
+        self::assertFalse($slot1->equals($slot2));
+    }
+
+    #[Test]
+    public function durationInMinutesReturnsCorrectValue(): void
+    {
+        $timeSlot = new TimeSlot('08:00', '09:30');
+
+        self::assertSame(90, $timeSlot->durationInMinutes());
+    }
+}