Feature/fund escrow modal 68

[mijinummi]

Fund Escrow Modal with Stellar Transaction (#68)

Summary

This PR introduces a modal for funding escrows with Stellar wallet integration.
It allows sellers/buyers to connect their wallet, preview transaction details, sign, and submit securely.

Changes

• Added FundEscrowModal.tsx under frontend/components/escrow/modals/
• Integrated with WalletContext for Freighter/Albedo wallet signing
• Displayed funding amount, fees, and total before signing
• Implemented transaction status tracking:
  • Pending
  • Success (with transaction hash)
  • Failed (error handling)
• Added UI for transaction preview and confirmation

Acceptance Criteria Covered

• ✅ Fund Escrow button triggers modal
• ✅ Wallet integration for signing
• ✅ Transaction preview before signing
• ✅ Transaction status tracking
• ✅ Stellar transaction hash displayed on success

Testing

• Verified wallet connection flow
• Verified transaction signing UX
• Verified error handling for wallet rejection
• Verified success flow with transaction hash display

Next Steps

• Connect modal to backend escrow funding API
• Add styling and UX improvements
• Expand test coverage for edge cases
  Closes Implement Fund Escrow Modal with Stellar Transaction #68

[Cedarich]

Please boss address build errors

Run npm run build