Add Lottie global loading overlay and fix stuck loading states.

Replace per-VC activity indicators with a ref-counted GlobalLoadingManager, and resolve duplicate show/hide calls on Profile, Statistics, and Home tabs.

Co-authored-by: Cursor <cursoragent@cursor.com>

suixinkan/UI/Statistics/StatisticsViewController.swift

@@ -91,16 +91,13 @@ final class StatisticsViewController: BaseViewController {
     }
 
     private func initializeStatistics() async {
-        showLoading()
         await viewModel.initStatistics(api: statisticsAPI)
-        hideLoading()
+        applyViewModel()
     }
 
     private func selectPeriod(_ period: String) {
         Task {
-            showLoading()
             await viewModel.selectPeriod(period, api: statisticsAPI)
-            hideLoading()
         }
     }