修复白屏BUG、UI 边界溢出 BUG

lib/features/profile/presentation/avatar_image.dart

@@ -0,0 +1,19 @@
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+
+import 'package:arcx/core/constants/app_defaults.dart';
+import 'package:arcx/data/local/models/models.dart';
+
+/// Resolves a profile avatar to a local file when present, otherwise the
+/// default asset. Missing local files fall back safely (no FileImage crash).
+ImageProvider resolveAvatarImage(UserProfile? profile) {
+  final path = profile?.avatarLocalPath?.trim();
+  if (profile?.avatarSource == AvatarSource.localFile &&
+      path != null &&
+      path.isNotEmpty &&
+      File(path).existsSync()) {
+    return FileImage(File(path));
+  }
+  return const AssetImage(AppDefaults.defaultAvatarAssetPath);
+}

lib/features/profile/presentation/profile_edit_dialog.dart

@@ -1,12 +1,10 @@
-import 'dart:io';
-
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import 'package:arcx/app/app_theme.dart';
-import 'package:arcx/core/constants/app_defaults.dart';
 import 'package:arcx/data/local/models/models.dart';
 import 'package:arcx/features/profile/application/profile_controller.dart';
+import 'package:arcx/features/profile/presentation/avatar_image.dart';
 
 class ProfileEditDialog extends ConsumerStatefulWidget {
   const ProfileEditDialog({super.key});
@@ -137,23 +135,13 @@ class _AvatarPreview extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final p = profile;
-    final ImageProvider image;
-    if (p != null &&
-        p.avatarSource == AvatarSource.localFile &&
-        p.avatarLocalPath != null &&
-        p.avatarLocalPath!.isNotEmpty) {
-      image = FileImage(File(p.avatarLocalPath!));
-    } else {
-      image = const AssetImage(AppDefaults.defaultAvatarAssetPath);
-    }
     return Stack(
       alignment: Alignment.bottomRight,
       children: [
         CircleAvatar(
           radius: 44,
           backgroundColor: AppTheme.surfaceMuted,
-          backgroundImage: image,
+          backgroundImage: resolveAvatarImage(profile),
         ),
         Container(
           padding: const EdgeInsets.all(6),