feat(front): implement AM couple selector (#170)

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/lib/widgets/quotidien/couple_selector_bandeau.dart

@@ -135,6 +135,16 @@ class _CoupleCard extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    // Parent mode: enfant | AM
+    // AM mode: enfant | parent(s)
+    final isParentMode = mode == CoupleBandeauMode.parent;
+    final fallbackRoleIcon = isParentMode ? Icons.volunteer_activism : Icons.person_outline;
+    final fallbackRoleName = isParentMode ? 'Nounou' : 'Parent';
+    
+    // TODO: In AM mode, we should ideally display "parent1+parent2 empilés" or centered.
+    // For now, CoupleGarde only gives us `am` (which in AM mode might just represent one parent, or the system needs to feed both parents here). 
+    // Assuming backend will populate `am` field with the parent data when called by AM.
+
     return Container(
       height: 90,
       decoration: BoxDecoration(
@@ -175,14 +185,8 @@ class _CoupleCard extends StatelessWidget {
                 photoUrl: couple.am.photoUrl,
                 name: (couple.am.prenom != null && couple.am.prenom!.isNotEmpty)
                     ? couple.am.prenom!
-                    : couple.am.displayName(
-                        fallback: mode == CoupleBandeauMode.parent
-                            ? 'Nounou'
-                            : 'Parent',
-                      ),
-                fallbackIcon: mode == CoupleBandeauMode.parent
-                    ? Icons.volunteer_activism
-                    : Icons.person_outline,
+                    : couple.am.displayName(fallback: fallbackRoleName),
+                fallbackIcon: fallbackRoleIcon,
               ),
             ),
           ),