feat: model and user avatars

lib/core/utils/user_avatar_utils.dart

@@ -0,0 +1,95 @@
+import '../models/user.dart' as models;
+import '../services/api_service.dart';
+
+String? deriveUserProfileImage(dynamic user) {
+  if (user == null) return null;
+
+  String? pick(dynamic source) {
+    if (source is Map) {
+      for (final key in const [
+        'profile_image_url',
+        'profileImage',
+        'avatar_url',
+        'avatar',
+        'picture',
+        'image',
+      ]) {
+        final value = source[key];
+        if (value is String && value.trim().isNotEmpty) {
+          return value.trim();
+        }
+      }
+    }
+    return null;
+  }
+
+  if (user is models.User) {
+    final value = user.profileImage;
+    if (value != null && value.trim().isNotEmpty) {
+      return value.trim();
+    }
+    return null;
+  }
+
+  final topLevel = pick(user);
+  if (topLevel != null) return topLevel;
+
+  if (user is Map && user['user'] != null) {
+    final nested = pick(user['user']);
+    if (nested != null) return nested;
+  }
+
+  return null;
+}
+
+String? resolveUserProfileImageUrl(ApiService? api, String? rawUrl) {
+  final value = rawUrl?.trim();
+  if (value == null || value.isEmpty) {
+    return null;
+  }
+
+  if (value.startsWith('data:image')) {
+    return value;
+  }
+
+  if (value.startsWith('http://') || value.startsWith('https://')) {
+    return value;
+  }
+
+  if (value.startsWith('//')) {
+    final base = api?.baseUrl;
+    if (base != null && base.isNotEmpty) {
+      try {
+        final baseUri = Uri.parse(base);
+        final scheme = baseUri.scheme.isNotEmpty ? baseUri.scheme : 'https';
+        return '$scheme:$value';
+      } catch (_) {
+        return 'https:$value';
+      }
+    }
+    return 'https:$value';
+  }
+
+  if (api == null || api.baseUrl.isEmpty) {
+    return value.startsWith('/') ? value : '/$value';
+  }
+
+  try {
+    final baseUri = Uri.parse(api.baseUrl);
+    final resolved = baseUri.resolve(value);
+    return resolved.toString();
+  } catch (_) {
+    final normalizedBase = api.baseUrl.endsWith('/')
+        ? api.baseUrl.substring(0, api.baseUrl.length - 1)
+        : api.baseUrl;
+    if (value.startsWith('/')) {
+      return '$normalizedBase$value';
+    }
+    return '$normalizedBase/$value';
+  }
+}
+
+String? resolveUserAvatarUrlForUser(ApiService? api, dynamic user) {
+  final raw = deriveUserProfileImage(user);
+  return resolveUserProfileImageUrl(api, raw);
+}