feat(mine): 我的 Tab UI 重设计（#39~#41）

- ProfileHeroCard：72pt 渐变头像（8色 uid%8 主题）、@J{uid} handle、bio 简介、掩码手机号
- AppBar：compact，右侧 QR 图标 + 编辑铅笔
- 彩色图标行（_IconBox 36pt 圆角）+ 4 卡片组对齐 iOS SettingsView
  - 账户：我的钱包 / 账户安全
  - 工具：收藏 / 最近呼叫 / 链接设备 / 聊天文件夹
  - 偏好设置：通知和声音 / 隐私设置 / 黑名单 / 语言 / 主题
  - 关于：用户协议 / 隐私政策 / 版本号
- SettingsState 增加 bio 字段（#41），loadProfile 同步赋值
- Doc/mine_tab_architecture.md 补充 UI 重设计章节（§7）

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/im_app/lib/features/settings/presentation/settings_view_model.dart

@@ -12,6 +12,7 @@ class SettingsState {
   final String? avatarUrl;
   final String maskedContact;
   final int uid;
+  final String bio;
   final bool isLoading;
   final bool isLoggingOut;
   final String? error;
@@ -21,6 +22,7 @@ class SettingsState {
     this.avatarUrl,
     this.maskedContact = '',
     this.uid = 0,
+    this.bio = '',
     this.isLoading = false,
     this.isLoggingOut = false,
     this.error,
@@ -32,6 +34,7 @@ class SettingsState {
     bool clearAvatarUrl = false,
     String? maskedContact,
     int? uid,
+    String? bio,
     bool? isLoading,
     bool? isLoggingOut,
     String? error,
@@ -42,6 +45,7 @@ class SettingsState {
       avatarUrl: clearAvatarUrl ? null : (avatarUrl ?? this.avatarUrl),
       maskedContact: maskedContact ?? this.maskedContact,
       uid: uid ?? this.uid,
+      bio: bio ?? this.bio,
       isLoading: isLoading ?? this.isLoading,
       isLoggingOut: isLoggingOut ?? this.isLoggingOut,
       error: clearError ? null : (error ?? this.error),
@@ -84,6 +88,7 @@ class SettingsViewModel extends Notifier<SettingsState> {
         avatarUrl: profile.profilePic.isEmpty ? null : profile.profilePic,
         maskedContact: _maskContact(profile.contact, profile.countryCode),
         uid: profile.uid,
+        bio: profile.bio,
       );
     } catch (e) {
       state = state.copyWith(isLoading: false, error: e.toString());