feat(tx): block wrong network and account transactions (#925)

[s6pa1rta3n-lab]

Summary

Resolves #925 by introducing transaction preflight validation, explicit network switching actions, confirmation summaries, and account authority checks before transaction submission.

Changes

• Preflight Types & Validation (src/types/transactionPreflight.ts, src/utils/transactionPreflight.ts):
  • Added pure normalization and validation utilities for network names and account public keys.
  • Implemented evaluatePreflight() returning status (ready, wrong_network, wrong_account, not_connected, stale_account), specific error messages, and signing readiness flag.
• Hook Layer (src/hooks/useTransactionPreflight.ts):
  • Created useTransactionPreflight managing live wallet status, preflight states, explicit network switching, identity drift detection, and safe execution (executeSafeSubmit).
  • Guarantees network switch failures never auto-submit transactions.
• Accessible UI Components (src/components/TransactionConfirmationSummary.tsx, src/components/TransactionPreflightGuard.tsx, src/components/TransactionPreflightGuard.css):
  • Render confirmation summary with explicit network and account match badges.
  • Render accessible switch network action buttons and error banners.
  • Add identity change warning and explicit acknowledgement actions when wallet changes mid-flow.
• Modal & Flow Integration:
  • Integrated preflight checks and confirmation summaries into RepayModal.tsx, QuickRepayModal.tsx, RepayPreviewModal.tsx, and AmountConfirm.tsx.
  • Block confirmation buttons when preflight criteria are not met (canSign is false or isSwitching is true).
  • Execute preflight re-evaluation at submission time to eliminate race conditions.

Acceptance Criteria Verification

• Wrong network blocks signing.
• Expected account is compared with connected account.
• Switch failures do not auto-submit.
• Tests cover disconnect, switch, and stale account state.
• Unit and integration test suites passing (71 tests across 8 test files).
• Production build passes with zero errors.

Payout Routing

• EVM (Base/Arbitrum/Polygon/ETH): 0xF46C9F6d70C50BF81ef3588AB523a90a594a2F89
• Stellar: GCL6OXAMLD75BMTINA6EMRUDWK5THQUSHMYNLSNBCJAPZJHNYJTUNIBC