Build cross-chain payment initiation UI with live bridge fee estimation

[Kingsman-99]

Overview

Allow payers on Ethereum or Solana to pay a StellarSplit invoice from the app UI, without needing a Stellar wallet. Build a cross-chain payment flow that estimates bridge fees, shows the net amount, and guides the user through the bridge process.

Requirements

• "Pay from Another Chain" button on invoice detail page
• Chain selector: Ethereum Mainnet, Solana Mainnet
• Live fee estimation: as user selects chain, show Bridge Fee, Net Amount Received, Estimated Time
• "Connect MetaMask" / "Connect Phantom" wallet step (for Ethereum/Solana respectively)
• Build and display the bridge payment request using SDK buildBridgePayment
• Submit button triggers bridge payment → shows transaction hash + tracking link
• Polling progress: poll bridge status and update UI until Stellar-side relay is confirmed
• Write unit tests for the fee estimation component and chain selector

Acceptance Criteria

• Chain selector with live fee estimation works
• MetaMask and Phantom wallet connections work
• Bridge payment submission calls SDK correctly
• Progress polling updates UI until relay confirmed
• npm run lint passes with zero errors
• TypeScript compiles with zero errors
• npm run build succeeds

Definition of Done

All CI checks must pass before the PR is reviewed.

[nurudeenheroic]

I'd be happy to contribute and deliver a reliable solution.

[obedebuka41-dotcom]

i will like to fix this

[obedebuka41-dotcom]

i will like to fix this

[grantfox-oss]

🦊 GrantFox — @obedebuka41-dotcom has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #390)
2. Your PR will be reviewed by the Stellar-split maintainers

Good luck! Track your progress on GrantFox.