feat: 充值、划转、提现页面改用 Material Design 3 输入框

- deposit_page.dart: 金额输入框改用 MaterialInput
- transfer_page.dart: 金额输入框改用 MaterialInput
- withdraw_page.dart: 金额、地址、联系方式输入框改用 MaterialInput
- 保持所有业务逻辑和验证逻辑不变
- 统一视觉风格（圆角边框 + Focus 效果）

flutter_monisuo/lib/ui/pages/asset/transfer_page.dart

@@ -6,6 +6,7 @@ import '../../../core/theme/app_theme.dart';
 import '../../../core/theme/app_spacing.dart';
 import '../../../providers/asset_provider.dart';
 import '../../../data/models/account_models.dart';
+import '../../components/material_input.dart';
 
 /// 划转页面
 class TransferPage extends StatefulWidget {
@@ -365,60 +366,25 @@ class _TransferPageState extends State<TransferPage> {
         const SizedBox(height: 12),
 
         // 金额输入框
-        Container(
-          width: double.infinity,
-          height: 52,
-          decoration: BoxDecoration(
-            color: colorScheme.surface,
-            borderRadius: BorderRadius.circular(14),
-            border: Border.all(
-              color: _focusNode.hasFocus
-                  ? colorScheme.secondary
-                  : colorScheme.outlineVariant.withValues(alpha: 0.5),
-              width: 1,
+        MaterialInput(
+          controller: _amountController,
+          focusNode: _focusNode,
+          hintText: '0.00',
+          keyboardType: const TextInputType.numberWithOptions(decimal: true),
+          inputFormatters: [
+            FilteringTextInputFormatter.allow(RegExp(r'^\d*\.?\d{0,8}')),
+          ],
+          onChanged: (_) => setState(() {}),
+          suffixIcon: Padding(
+            padding: const EdgeInsets.only(right: AppSpacing.md),
+            child: Text(
+              'USDT',
+              style: AppTextStyles.bodyMedium(context).copyWith(
+                color: colorScheme.onSurfaceVariant,
+                fontWeight: FontWeight.w500,
+              ),
             ),
           ),
-          padding: const EdgeInsets.symmetric(horizontal: 16),
-          child: Row(
-            children: [
-              Expanded(
-                child: TextField(
-                  controller: _amountController,
-                  focusNode: _focusNode,
-                  keyboardType:
-                      const TextInputType.numberWithOptions(decimal: true),
-                  inputFormatters: [
-                    FilteringTextInputFormatter.allow(
-                        RegExp(r'^\d*\.?\d{0,8}')),
-                  ],
-                  style: TextStyle(
-                    fontSize: 24,
-                    fontWeight: FontWeight.w600,
-                    color: colorScheme.onSurface,
-                  ),
-                  decoration: InputDecoration(
-                    hintText: '0.00',
-                    hintStyle: TextStyle(
-                      fontSize: 24,
-                      fontWeight: FontWeight.w600,
-                      color: colorScheme.onSurfaceVariant.withValues(alpha: 0.3),
-                    ),
-                    border: InputBorder.none,
-                    contentPadding: EdgeInsets.zero,
-                    isDense: true,
-                  ),
-                  onChanged: (_) => setState(() {}),
-                ),
-              ),
-              Text(
-                'USDT',
-                style: AppTextStyles.bodyMedium(context).copyWith(
-                  color: colorScheme.onSurfaceVariant,
-                  fontWeight: FontWeight.w500,
-                ),
-              ),
-            ],
-          ),
         ),
         const SizedBox(height: 10),