Ajout diagram de gantt

src/app/milestones/milestone-detail/milestone-detail.html

@@ -47,6 +47,26 @@
   <div class="card-header section-header">Informations</div>
   <div class="card-body">
     <div class="row g-3">
+      <div class="col-md-4">
+        <label class="field-label">Date de début</label>
+        <input
+          aria-label="Date de début"
+          class="form-control form-control-sm"
+          type="date"
+          [(ngModel)]="milestone.startDate"
+          (blur)="saveMilestone()"
+        />
+      </div>
+      <div class="col-md-4">
+        <label class="field-label">Date de fin</label>
+        <input
+          aria-label="Date de fin"
+          class="form-control form-control-sm"
+          type="date"
+          [(ngModel)]="milestone.endDate"
+          (blur)="saveMilestone()"
+        />
+      </div>
       <div class="col-md-4">
         <label class="field-label">Date d'échéance</label>
         <input
@@ -237,6 +257,16 @@
   </div>
 </div>
 
+<!-- Diagramme Gantt -->
+@if (!isNewRoute) {
+  <div class="card shadow-sm mb-3">
+    <div class="card-header section-header">Diagramme Gantt</div>
+    <div class="card-body">
+      <app-gantt-diagram [tasks]="milestoneGanttTasks" />
+    </div>
+  </div>
+}
+
 <!-- Boutons de création -->
 @if (isNewRoute) {
   <div class="d-flex gap-2">