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/composables/useEmployeeRtt.ts

@@ -1,4 +1,5 @@
 import type { Ref } from 'vue'
+import type { ContractPhase } from '~/services/dto/contract-phase'
 import type { EmployeeRttSummary } from '~/services/dto/employee-rtt-summary'
 import type { Employee } from '~/services/dto/employee'
 import { getEmployeeRttSummary, createRttPayment } from '~/services/employee-rtt-summary'
@@ -8,7 +9,11 @@ export type RttYearOption = {
   label: string
 }
 
-export const useEmployeeRtt = (employee: Ref<Employee | null>, reloadEmployee: () => Promise<void>) => {
+export const useEmployeeRtt = (
+  employee: Ref<Employee | null>,
+  reloadEmployee: () => Promise<void>,
+  selectedPhase: Ref<ContractPhase | null>,
+) => {
   const rttSummary = ref<EmployeeRttSummary | null>(null)
   const isRttLoading = ref(false)
   const rttDataLoaded = ref(false)
@@ -25,22 +30,14 @@ export const useEmployeeRtt = (employee: Ref<Employee | null>, reloadEmployee: (
   })
 
   const availableRttYears = computed<RttYearOption[]>(() => {
-    if (!employee.value || currentRttYear.value === null) return []
-    const current = currentRttYear.value
+    if (!employee.value || !selectedPhase.value || currentRttYear.value === null) return []
+    const phase = selectedPhase.value
 
-    const startDates: string[] = []
-    for (const period of employee.value.contractHistory ?? []) {
-      if (period.startDate) startDates.push(period.startDate)
-    }
-    if (employee.value.entryDate) startDates.push(employee.value.entryDate)
-
-    let contractFloor = current
-    for (const raw of startDates) {
-      const date = new Date(`${raw.substring(0, 10)}T00:00:00`)
-      if (Number.isNaN(date.getTime())) continue
-      const rttYear = computeRttYearForDate(date)
-      if (rttYear < contractFloor) contractFloor = rttYear
-    }
+    // Plage = exercices intersectant la phase.
+    const phaseStartYear = computeRttYearForDate(new Date(`${phase.startDate}T00:00:00`))
+    const phaseEndYear = phase.endDate
+      ? computeRttYearForDate(new Date(`${phase.endDate}T00:00:00`))
+      : currentRttYear.value
 
     // Hard floor : rttStartDate (env RTT_START_DATE) — pas d'historique avant.
     let dataFloor: number | null = null
@@ -52,10 +49,11 @@ export const useEmployeeRtt = (employee: Ref<Employee | null>, reloadEmployee: (
       }
     }
 
-    const minYear = dataFloor !== null ? Math.max(contractFloor, dataFloor) : contractFloor
+    const minYear = dataFloor !== null ? Math.max(phaseStartYear, dataFloor) : phaseStartYear
+    const maxYear = phaseEndYear
 
     const years: RttYearOption[] = []
-    for (let y = current; y >= minYear; y -= 1) {
+    for (let y = maxYear; y >= minYear; y -= 1) {
       years.push({ value: y, label: `Juin ${y - 1} → Mai ${y}` })
     }
     return years
@@ -74,7 +72,11 @@ export const useEmployeeRtt = (employee: Ref<Employee | null>, reloadEmployee: (
     if (selectedRttYear.value === null) return
     isRttLoading.value = true
     try {
-      rttSummary.value = await getEmployeeRttSummary(employee.value.id, selectedRttYear.value)
+      rttSummary.value = await getEmployeeRttSummary(
+        employee.value.id,
+        selectedRttYear.value,
+        selectedPhase.value?.id,
+      )
       rttDataLoaded.value = true
     } finally {
       isRttLoading.value = false
@@ -93,6 +95,13 @@ export const useEmployeeRtt = (employee: Ref<Employee | null>, reloadEmployee: (
     selectedRttYear.value = null
   }
 
+  watch(() => selectedPhase.value?.id, () => {
+    // Reset l'année car la plage a peut-être changé.
+    selectedRttYear.value = null
+    rttDataLoaded.value = false
+    // Le rechargement effectif est piloté par useEmployeeDetailPage.
+  })
+
   const submitRttPayment = async (month: number, base25Minutes: number, bonus25Minutes: number, base50Minutes: number, bonus50Minutes: number) => {
     if (!employee.value) return
     const year = rttSummary.value?.year ?? undefined