refactor(trading): rename 黑洞 to 积分股池

- Update market data label from 黑洞销毁量 to 积分股池
- Update 10% 进入黑洞 to 10% 进入积分股池
- Update sell confirmation dialog text
- Update entity comments to reflect new naming

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

frontend/mining-app/lib/domain/entities/market_overview.dart

@@ -6,7 +6,7 @@ class MarketOverview extends Equatable {
   final String price;
   /// 积分值池
   final String greenPoints;
-  /// 黑洞销毁量
+  /// 积分股池
   final String blackHoleAmount;
   /// 流通池
   final String circulationPool;

frontend/mining-app/lib/domain/entities/price_info.dart

@@ -6,7 +6,7 @@ class PriceInfo extends Equatable {
   final String price;
   /// 积分值池
   final String greenPoints;
-  /// 黑洞销毁量
+  /// 积分股池
   final String blackHoleAmount;
   /// 流通池
   final String circulationPool;

frontend/mining-app/lib/presentation/pages/trading/trading_page.dart

@@ -304,9 +304,9 @@ class _TradingPageState extends ConsumerState<TradingPage> {
               Container(width: 1, height: 24, color: _bgGray),
               const SizedBox(width: 16),
               _buildMarketDataItem(
-                '黑洞销毁量',
+                '积分股池',
                 market != null ? formatCompact(market.blackHoleAmount) : null,
-                _red,
+                _green,
                 isLoading,
               ),
             ],
@@ -507,10 +507,10 @@ class _TradingPageState extends ConsumerState<TradingPage> {
                     style: TextStyle(fontSize: 12, color: _grayText),
                   ),
                   Text(
-                    '10% 进入黑洞',
+                    '10% 进入积分股池',
                     style: TextStyle(
                       fontSize: 12,
-                      color: _red,
+                      color: _green,
                       fontFamily: 'monospace',
                     ),
                   ),
@@ -928,8 +928,8 @@ class _TradingPageState extends ConsumerState<TradingPage> {
               Text('交易总额: ${formatAmount(total.toString())} 积分值'),
               const SizedBox(height: 8),
               Text(
-                '销毁金额: ${formatAmount(burned.toString())} 积分值 (10%)',
-                style: const TextStyle(color: _red),
+                '进入积分股池: ${formatAmount(burned.toString())} 积分值 (10%)',
+                style: const TextStyle(color: _green),
               ),
               const SizedBox(height: 8),
               Text(
@@ -941,7 +941,7 @@ class _TradingPageState extends ConsumerState<TradingPage> {
               ),
               const SizedBox(height: 16),
               const Text(
-                '注意: 卖出积分股将扣除10%进入黑洞销毁，此操作不可撤销。',
+                '注意: 卖出积分股将扣除10%进入积分股池，此操作不可撤销。',
                 style: TextStyle(
                   fontSize: 12,
                   color: _grayText,