Merge branch 'feature/149-clic-case-libre-rattacher-enfant' into develop

Clic case libre → rattacher enfant (#149).

frontend/lib/widgets/admin/common/admin_am_children_capacity_grid.dart

@@ -20,6 +20,8 @@ class AdminAmChildrenCapacityGrid extends StatelessWidget {
   final int capacity;
   final void Function(ParentChildSummary child) onOpen;
   final void Function(ParentChildSummary child) onDetach;
+  /// Clic sur une case libre → même flux que « Rattacher un enfant » (#149).
+  final VoidCallback? onAttachEmpty;
 
   const AdminAmChildrenCapacityGrid({
     super.key,
@@ -27,6 +29,7 @@ class AdminAmChildrenCapacityGrid extends StatelessWidget {
     required this.capacity,
     required this.onOpen,
     required this.onDetach,
+    this.onAttachEmpty,
   });
 
   @override
@@ -78,7 +81,7 @@ class AdminAmChildrenCapacityGrid extends StatelessWidget {
       );
     }
     if (index < maxSlots) {
-      return const _EmptySlot();
+      return _EmptySlot(onTap: onAttachEmpty);
     }
     return const _UnavailableSlot();
   }
@@ -129,18 +132,52 @@ class _UnavailableSlot extends StatelessWidget {
   }
 }
 
-class _EmptySlot extends StatelessWidget {
+class _EmptySlot extends StatefulWidget {
-  const _EmptySlot();
+  final VoidCallback? onTap;
+
+  const _EmptySlot({this.onTap});
+
+  @override
+  State<_EmptySlot> createState() => _EmptySlotState();
+}
+
+class _EmptySlotState extends State<_EmptySlot> {
+  bool _hovered = false;
 
   @override
   Widget build(BuildContext context) {
-    return _SlotShell(
+    final clickable = widget.onTap != null;
-      backgroundColor: Colors.grey.shade50,
+    return MouseRegion(
-      borderColor: Colors.grey.shade300,
+      onEnter: clickable ? (_) => setState(() => _hovered = true) : null,
+      onExit: clickable ? (_) => setState(() => _hovered = false) : null,
+      cursor: clickable ? SystemMouseCursors.click : MouseCursor.defer,
+      child: Material(
+        color: Colors.transparent,
+        borderRadius: BorderRadius.circular(8),
+        child: InkWell(
+          onTap: widget.onTap,
+          borderRadius: BorderRadius.circular(8),
+          hoverColor: const Color(0x149CC5C0),
+          child: _SlotShell(
+            backgroundColor: _hovered
+                ? const Color(0xFFF3F0FA)
+                : Colors.grey.shade50,
+            borderColor: _hovered
+                ? const Color(0xFFB8A4D4)
+                : Colors.grey.shade300,
             child: Center(
               child: Text(
                 'Place libre',
-          style: TextStyle(fontSize: 12, color: Colors.grey.shade500),
+                style: TextStyle(
+                  fontSize: 12,
+                  color: _hovered
+                      ? const Color(0xFF6B3FA0)
+                      : Colors.grey.shade500,
+                  fontWeight: _hovered ? FontWeight.w600 : FontWeight.w400,
+                ),
+              ),
+            ),
+          ),
         ),
       ),
     );

frontend/lib/widgets/admin/common/admin_am_edit_modal.dart

@@ -745,6 +745,7 @@ class _AdminAmEditModalState extends State<AdminAmEditModal>
           capacity: capacity,
           onOpen: _openChild,
           onDetach: _detachChild,
+          onAttachEmpty: _capacityFull ? null : _attachChild,
         ),
       ],
     );