feat(recap-conges) : cutoff S-1 au lieu de S-2

Le récap des congés se fige désormais à la fin de la semaine précédente
(S-1) au lieu de l'avant-dernière (S-2), incluant ainsi une semaine de
plus. Demande métier.

- LeaveRecapCutoff : -14j -> -7j
- Test unitaire figeant la règle S-1
- Doc fonctionnelle, doc in-app et CLAUDE.md mis à jour

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/Util/LeaveRecapCutoffTest.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Util;
+
+use App\Util\LeaveRecapCutoff;
+use DateTimeImmutable;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Cutoff rule: end of ISO week S-1 (previous week's Sunday 23:59:59).
+ *
+ * @internal
+ */
+final class LeaveRecapCutoffTest extends TestCase
+{
+    public function testCutoffIsPreviousWeekSunday(): void
+    {
+        // Tuesday 2026-04-14 (S16) → Sunday 2026-04-12 23:59:59 (end of S15).
+        $cutoff = LeaveRecapCutoff::resolveCutoff(new DateTimeImmutable('2026-04-14'));
+
+        self::assertSame('2026-04-12 23:59:59', $cutoff->format('Y-m-d H:i:s'));
+    }
+
+    public function testCutoffFromMondayPointsToPreviousSunday(): void
+    {
+        // Monday 2026-06-08 → previous Sunday 2026-06-07 23:59:59.
+        $cutoff = LeaveRecapCutoff::resolveCutoff(new DateTimeImmutable('2026-06-08'));
+
+        self::assertSame('2026-06-07 23:59:59', $cutoff->format('Y-m-d H:i:s'));
+    }
+
+    public function testCutoffFromSundayPointsToPreviousSunday(): void
+    {
+        // Sunday 2026-06-14 (still in current ISO week) → previous Sunday 2026-06-07.
+        $cutoff = LeaveRecapCutoff::resolveCutoff(new DateTimeImmutable('2026-06-14'));
+
+        self::assertSame('2026-06-07 23:59:59', $cutoff->format('Y-m-d H:i:s'));
+    }
+
+    public function testCutoffIsAlwaysASundayExactlyOneWeekBeforeCurrentWeek(): void
+    {
+        // Today 2026-06-11 (Thursday) → end of S-1 = Sunday 2026-06-07.
+        $cutoff = LeaveRecapCutoff::resolveCutoff(new DateTimeImmutable('2026-06-11'));
+
+        self::assertSame('Sunday', $cutoff->format('l'));
+        self::assertSame('2026-06-07 23:59:59', $cutoff->format('Y-m-d H:i:s'));
+    }
+}