feat(leave) : align forfait CP N + display remaining workdays + N-1 absences exempt from presence

- LeaveRecapRowBuilder: forfait CP N now reflects remainingDays (acquis − pris depuis N) instead of the constant acquiredDays. Affects both PDF export and screen recap.
- Employee detail header: forfait label becomes "Forfait - 218 jours (X restants)" where X = 218 − presence days from Jan 1 to today (today included).
- New EmployeeLeaveSummary.presenceDaysToToday field, computed via the same logic as presenceDaysByMonth but capped at today.
- Forfait business rule: leaves attributed to N-1 stock no longer decrement presence days. Implemented by chronologically consuming an N-1 budget (= previousYearTakenDays) inside computePresenceDaysByMonth before counting any absence. Non-forfait unaffected (budget is 0).
- Doc updates: CLAUDE.md (forfait/N-1 rule), functional-rules.md (CP N forfait semantics).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -61,6 +61,7 @@
 - INTERIM: no overtime bonuses, no recovery time
 - Driver contracts: RTT uses `dayHoursMinutes + nightHoursMinutes + workshopHoursMinutes` instead of morning/afternoon/evening time ranges
 - FORFAIT weekend/holiday bonus: each weekend or public holiday day worked gives bonus leave (full day if morning+afternoon, 0.5 if only one). Added to acquired days, no cap. PRESENCE mode only.
+- **FORFAIT — jours de présence et N-1** : les congés posés et imputés sur le stock N-1 ne décrémentent **pas** les jours de présence affichés (`presenceDaysByMonth` et `presenceDaysToToday`). Implémenté dans `EmployeeLeaveSummaryProvider::computePresenceDaysByMonth` via un budget N-1 (= `previousYearTakenDays`) consommé chronologiquement avant comptage des absences. Pour les non-forfait, ce budget vaut toujours 0 → comportement inchangé.
 
 ## Récap. congés (écran)
 - Accès via sidebar `Récap. congés`, conditionné au flag `User.hasLeaveRecapAccess` (défaut `false`) — activé au create/edit user. Le flag s'applique à tous les profils, y compris admin.