fix(frontend): 修正市团队权益描述金额 30 → 40 USDT

市团队权益每棵树实际是 40 USDT，前端显示文案错误写成 30 USDT

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

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

frontend/mobile-app/lib/features/profile/presentation/pages/profile_page.dart

@@ -1142,7 +1142,7 @@ class _ProfilePageState extends ConsumerState<ProfilePage> {
               initialTarget: _authCityCompanyInitialTarget,
               monthlyTarget: _authCityCompanyMonthlyTarget,
               monthIndex: _authCityCompanyMonthIndex,
-              rewardDescription: '每新增认种 1 棵可获得 30 USDT',
+              rewardDescription: '每新增认种 1 棵可获得 40 USDT',
             ),
           ],
           // 省团队权益考核