Add Loading Indicators to All Screens

[MasterAffan]

Description:
Add proper loading indicators throughout the Flutter app to improve user experience during data fetching and processing.

Tasks:

• Add CircularProgressIndicator to home screen during video upload
• Add loading states to workout history screen
• Add shimmer effects to progress charts while loading
• Implement consistent loading widget across all screens
• Add loading text messages for better UX

Acceptance Criteria:

• Loading indicators appear during all async operations
• Consistent design across all screens
• No blank screens during loading
• Smooth transitions between loading and loaded states

[Tia-ani]

Hi @MasterAffan I’d like to work on this issue. Could you assign it to me?

[MasterAffan]

sure