refactor(mining-app): rename team contribution labels

Update contribution page labels:
- "团队层级" → "团队下级"
- "团队奖励" → "团队上级"
- "直推人数" → "引荐人数"
- "已解锁奖励" → "已解锁上级" (with unit "档" → "级")
- "已解锁层级" → "已解锁下级"
- "直推及间推" → "引荐及间推" in subtitle

Update contribution records page labels:
- "团队层级" → "团队下级"
- "团队奖励" → "团队上级"

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

frontend/mining-app/lib/presentation/pages/contribution/contribution_page.dart

@@ -82,7 +82,7 @@ class ContributionPage extends ConsumerWidget {
                           // 贡献值明细（三类汇总）
                           _buildContributionDetailCard(context, ref, contribution, isLoading),
                           const SizedBox(height: 16),
-                          // 团队层级统计
+                          // 团队下级统计
                           _buildTeamStatsCard(contribution, isLoading),
                           const SizedBox(height: 16),
                           // 贡献值失效倒计时
@@ -235,8 +235,8 @@ class ContributionPage extends ConsumerWidget {
       child: Row(
         children: [
           _buildStatColumn('个人贡献值', contribution?.personalContribution, isLoading, false, hideAmounts),
-          _buildStatColumn('团队层级', contribution?.teamLevelContribution, isLoading, true, hideAmounts),
+          _buildStatColumn('团队下级', contribution?.teamLevelContribution, isLoading, true, hideAmounts),
-          _buildStatColumn('团队奖励', contribution?.teamBonusContribution, isLoading, true, hideAmounts),
+          _buildStatColumn('团队上级', contribution?.teamBonusContribution, isLoading, true, hideAmounts),
         ],
       ),
     );
@@ -394,8 +394,8 @@ class ContributionPage extends ConsumerWidget {
                 _buildDetailSummaryRow(
                   icon: Icons.groups_outlined,
                   iconColor: Colors.blue,
-                  title: '团队层级',
+                  title: '团队下级',
-                  subtitle: '直推及间推用户认种产生的贡献值',
+                  subtitle: '引荐及间推用户认种产生的贡献值',
                   amount: contribution?.teamLevelContribution ?? '0',
                   hideAmounts: hideAmounts,
                 ),
@@ -403,7 +403,7 @@ class ContributionPage extends ConsumerWidget {
                 _buildDetailSummaryRow(
                   icon: Icons.card_giftcard_outlined,
                   iconColor: Colors.purple,
-                  title: '团队奖励',
+                  title: '团队上级',
                   subtitle: '满足条件后获得的额外奖励贡献值',
                   amount: contribution?.teamBonusContribution ?? '0',
                   hideAmounts: hideAmounts,
@@ -511,7 +511,7 @@ class ContributionPage extends ConsumerWidget {
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
           const Text(
-            '团队层级统计',
+            '团队下级统计',
             style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold, color: _darkText),
           ),
           const SizedBox(height: 16),
@@ -519,16 +519,16 @@ class ContributionPage extends ConsumerWidget {
           Row(
             children: [
               _buildTeamStatItem(
-                '直推人数',
+                '引荐人数',
                 contribution?.directReferralAdoptedCount.toString(),
                 '人',
                 isLoading,
               ),
               const SizedBox(width: 16),
               _buildTeamStatItem(
-                '已解锁奖励',
+                '已解锁上级',
                 contribution?.unlockedBonusTiers.toString(),
-                '档',
+                '级',
                 isLoading,
               ),
             ],
@@ -538,7 +538,7 @@ class ContributionPage extends ConsumerWidget {
           Row(
             children: [
               _buildTeamStatItem(
-                '已解锁层级',
+                '已解锁下级',
                 contribution?.unlockedLevelDepth.toString(),
                 '级',
                 isLoading,

frontend/mining-app/lib/presentation/pages/contribution/contribution_records_page.dart

@@ -101,9 +101,9 @@ class _ContributionRecordsListPageState extends ConsumerState<ContributionRecord
           const SizedBox(width: 8),
           _buildFilterChip('个人', ContributionSourceType.personal),
           const SizedBox(width: 8),
-          _buildFilterChip('团队层级', ContributionSourceType.teamLevel),
+          _buildFilterChip('团队下级', ContributionSourceType.teamLevel),
           const SizedBox(width: 8),
-          _buildFilterChip('团队奖励', ContributionSourceType.teamBonus),
+          _buildFilterChip('团队上级', ContributionSourceType.teamBonus),
         ],
       ),
     );
@@ -388,12 +388,12 @@ class _ContributionRecordsListPageState extends ConsumerState<ContributionRecord
         textColor = _orange;
         break;
       case ContributionSourceType.teamLevel:
-        label = '团队层级';
+        label = '团队下级';
         bgColor = Colors.blue.withOpacity(0.1);
         textColor = Colors.blue;
         break;
       case ContributionSourceType.teamBonus:
-        label = '团队奖励';
+        label = '团队上级';
         bgColor = Colors.purple.withOpacity(0.1);
         textColor = Colors.purple;
         break;