Add Error Handling and User Feedback

[Mrwicks00]

Description

Implement comprehensive error handling and user feedback for all contract interactions.

Tasks

• Create error message mapping for common contract errors:
  • "Submissions closed" → User-friendly message
  • "Voting closed" → User-friendly message
  • "Below min stake" → Show minimum stake amount
  • "Insufficient balance" → Show current balance
  • "User submissions limit" → Show max submissions
  • Transaction revert reasons
• Add toast notifications for:
  • Transaction pending
  • Transaction success
  • Transaction failure
  • Contract errors
• Display loading states during contract calls
• Add retry logic for failed transactions
• Show gas estimation errors before transaction
• Handle network errors gracefully
• Add error boundaries for React components

Files to Modify

• All hooks that interact with contracts
• frontend/lib/errorMessages.ts (new file - error message mapping)
• frontend/components/ui/toast.tsx (enhance existing)

[Ajith27887]

Can I work on this?