feat(ui): replace loading indicators with Apple-style LoadingSpinner

- Add LoadingSpinner component with small/medium/large sizes using system gray color
- Add LoadingPlaceholder for skeleton loading states
- Add LoadingSheet for full-screen blocking overlays
- Replace ThemedSpinner/ThemedSpinnerCompact across all views
- Remove deprecated loading components from AnimatedComponents.swift
- Delete LoadingTextGenerator.swift
- Fix PhotoImportView layout to fill full width

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

SportsTime/Export/Services/ProgressCardGenerator.swift

@@ -541,7 +541,8 @@ struct ProgressShareView: View {
         } label: {
             HStack {
                 if isGenerating {
-                    ThemedSpinnerCompact(size: 18, color: .white)
+                    LoadingSpinner(size: .small)
+                        .colorScheme(.dark)
                 } else {
                     Image(systemName: "square.and.arrow.up")
                 }