fix(mobile-app): 隐藏提取页面的网络选择功能

- 提取绿积分页面隐藏"选择网络"组件
- 确认提取页面隐藏"提取网络"显示行
- 保留原有网络功能逻辑不变

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mobile-app/lib/features/withdraw/presentation/pages/withdraw_confirm_page.dart

@@ -463,8 +463,9 @@ class _WithdrawConfirmPageState extends ConsumerState<WithdrawConfirmPage> {
             ),
           ),
           const SizedBox(height: 16),
-          _buildDetailRow('提取网络', _getNetworkName(widget.params.network)),
-          const SizedBox(height: 12),
+          // 隐藏提取网络显示（保留原有功能）
+          // _buildDetailRow('提取网络', _getNetworkName(widget.params.network)),
+          // const SizedBox(height: 12),
           _buildDetailRow('接收账号', _formatAddress(widget.params.address)),
           const SizedBox(height: 12),
           _buildDetailRow('提取数量', '${widget.params.amount.toStringAsFixed(2)} 绿积分'),

frontend/mobile-app/lib/features/withdraw/presentation/pages/withdraw_usdt_page.dart

@@ -378,9 +378,9 @@ class _WithdrawUsdtPageState extends ConsumerState<WithdrawUsdtPage> {
                                 _buildBalanceCard(),
                                 const SizedBox(height: 24),
 
-                                // 网络选择
-                                _buildNetworkSelector(),
-                                const SizedBox(height: 24),
+                                // 隐藏网络选择（保留原有功能）
+                                // _buildNetworkSelector(),
+                                // const SizedBox(height: 24),
 
                                 // 提款地址
                                 _buildAddressInput(),