feat(#140): fiches admin famille — IdentityBlock, parsing enfants et avatars web

Extrait IdentityBlock réutilisable, aligne les modales parent/enfant sur le style validation, corrige le parsing parentChildren et les URLs /uploads en Flutter web.

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

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

@@ -1,4 +1,6 @@
 import 'package:flutter/material.dart';
+import 'package:p_tits_pas/services/api/api_config.dart';
+import 'package:p_tits_pas/widgets/common/auth_network_image.dart';
 
 class AdminUserCard extends StatefulWidget {
   final String title;
@@ -37,6 +39,7 @@ class _AdminUserCardState extends State<AdminUserCard> {
         widget.subtitleLines.where((e) => e.trim().isNotEmpty).join('   ');
     final actionsWidth =
         widget.actions.isNotEmpty ? widget.actions.length * 30.0 : 0.0;
+    final avatarUrl = ApiConfig.absoluteMediaUrl(widget.avatarUrl);
 
     return MouseRegion(
       onEnter: (_) => setState(() => _isHovered = true),
@@ -60,20 +63,7 @@ class _AdminUserCardState extends State<AdminUserCard> {
               padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 9),
               child: Row(
                 children: [
-                  CircleAvatar(
-                    radius: 14,
-                    backgroundColor: const Color(0xFFEDE5FA),
-                    backgroundImage: widget.avatarUrl != null
-                        ? NetworkImage(widget.avatarUrl!)
-                        : null,
-                    child: widget.avatarUrl == null
-                        ? Icon(
-                            widget.fallbackIcon,
-                            size: 16,
-                            color: const Color(0xFF6B3FA0),
-                          )
-                        : null,
-                  ),
+                  _buildAvatar(avatarUrl),
                   const SizedBox(width: 10),
                   Expanded(
                     child: Row(
@@ -140,4 +130,35 @@ class _AdminUserCardState extends State<AdminUserCard> {
       ),
     );
   }
+
+  Widget _buildAvatar(String url) {
+    const size = 28.0;
+    const bg = Color(0xFFEDE5FA);
+    const iconColor = Color(0xFF6B3FA0);
+
+    if (url.isEmpty) {
+      return CircleAvatar(
+        radius: 14,
+        backgroundColor: bg,
+        child: Icon(widget.fallbackIcon, size: 16, color: iconColor),
+      );
+    }
+
+    return ClipOval(
+      child: SizedBox(
+        width: size,
+        height: size,
+        child: AuthNetworkImage(
+          url: url,
+          width: size,
+          height: size,
+          fit: BoxFit.cover,
+          errorBuilder: (_, __, ___) => ColoredBox(
+            color: bg,
+            child: Icon(widget.fallbackIcon, size: 16, color: iconColor),
+          ),
+        ),
+      ),
+    );
+  }
 }