Gestion du changement de type de contrat + correction du calcule des RTT sur un contrat qui commence en milieu de semaine (#19)

| Numéro du ticket | Titre du ticket |
|------------------|-----------------|
|                  |                 |

## Description de la PR

## Modification du .env

## Check list

- [x] Pas de régression
- [x] TU/TI/TF rédigée
- [x] TU/TI/TF OK
- [x] CHANGELOG modifié

Reviewed-on: #19
Co-authored-by: tristan <tristan@yuno.malio.fr>
Co-committed-by: tristan <tristan@yuno.malio.fr>

frontend/components/employees/RttTab.vue

@@ -28,7 +28,7 @@
         <div class="flex justify-center">
             <button
                 class="rounded-md bg-primary-500 px-8 py-2 font-bold text-white hover:bg-primary-600 disabled:opacity-40 disabled:cursor-not-allowed"
-                :disabled="isHistoricalYear"
+                :disabled="isPayDisabled"
                 @click="openPaymentDrawer"
             >
                 + Payer les RTT
@@ -276,6 +276,7 @@
 
 <script setup lang="ts">
 import type { EmployeeRttSummary, EmployeeRttWeekSummary } from '~/services/dto/employee-rtt-summary'
+import type { ContractPhase } from '~/services/dto/contract-phase'
 import AppDrawer from '~/components/AppDrawer.vue'
 
 type RttYearOption = {
@@ -288,6 +289,7 @@ const props = defineProps<{
   selectedYear: number | null
   availableYears: RttYearOption[]
   currentYear: number | null
+  selectedPhase: ContractPhase | null
 }>()
 
 const emit = defineEmits<{
@@ -301,6 +303,20 @@ const isHistoricalYear = computed(() =>
   && props.selectedYear !== props.currentYear
 )
 
+const isLastExerciseOfPhase = computed(() => {
+  if (!props.selectedPhase || props.selectedPhase.isCurrent) return false
+  if (!props.selectedPhase.endDate) return false
+  const endDate = new Date(`${props.selectedPhase.endDate}T00:00:00`)
+  const endYear = endDate.getMonth() >= 5
+    ? endDate.getFullYear() + 1
+    : endDate.getFullYear()
+  return props.selectedYear === endYear
+})
+
+const isPayDisabled = computed(() =>
+  isHistoricalYear.value && !isLastExerciseOfPhase.value
+)
+
 const handleYearChange = (event: Event) => {
   const target = event.target as HTMLSelectElement
   const value = Number(target.value)