refactor(frontend): update UI text labels

- Change contribution page subtitle to '股行用户引荐'
- Change receive shares page text from '手机号' to '账号'

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

frontend/mining-app/lib/presentation/pages/asset/receive_shares_page.dart

@@ -199,7 +199,7 @@ class ReceiveSharesPage extends ConsumerWidget {
       child: Column(
         children: [
           const Text(
-            '或告诉对方您的手机号',
+            '或告诉对方您的账号',
             style: TextStyle(
               fontSize: 14,
               color: _grayText,

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

@@ -425,7 +425,7 @@ class ContributionPage extends ConsumerWidget {
                   icon: Icons.groups_outlined,
                   iconColor: Colors.blue,
                   title: '团队下贡献值',
-                  subtitle: '引荐及间推用户参与产生的贡献值',
+                  subtitle: '股行用户引荐',
                   amount: contribution?.teamLevelContribution ?? '0',
                   hideAmounts: hideAmounts,
                 ),