Enable Set Router execution on the Swap page

[stxphxn]

Summary

Migrate BSC testnet swaps from direct Set contract execution to the deployed Set Router while preserving pool/poolId internally and using Set in user-facing copy.

Current gap

The Swap page still requests direct firm quotes, approves the Set contract, checks wallet-to-Set allowance, and accepts direct swapExact... calldata. Router-mode RFQ responses target 0x00355Ed1Fc7cD618AEC5A8E8fD31686376499ccB, require wallet-to-Router approval, include nested Router authorization, and execute swapSetwise.

Required outcomes

• Router-mode firm quotes are requested and validated fail-closed.
• ERC20 approvals and allowance reads target only the verified Router.
• ERC20-to-ERC20, native-to-ERC20, and ERC20-to-native swaps work from the Swap page.
• Stale, wrong-chain, wrong-Router, modified-calldata, paused, and replayed submissions remain blocked.
• The app performs submission preflight and records confirmed activity.
• Deposits and withdrawals remain direct-to-Set.

External prerequisites

• Complete BSC testnet Router acceptance setwise-router#80
• cenodev/setwise-rfq-api#14

Difficulty

High — cross-cutting wallet, schema, authorization, execution, and release work.

Completion

Complete all linked sub-issues and the BSC testnet wallet smoke matrix before deploying the app.