fix: validate batch buy liquid balance

[samjay8]

Closes #832

Summary

• Validate the combined quantity of batch recipient rows against the available liquid balance.
• Reject malformed Stellar recipient addresses and disable confirmation until all rows are valid.
• Submit only the validated address and quantity pairs to the batch mutation.

Scope

Does not change the separate marketing-links issue (#428) or unrelated batch-buy behavior.

Testing

• corepack pnpm exec vitest run src/components/common/__tests__/BatchBuyModal.test.tsx — passed (5 tests)
• corepack pnpm lint — passed
• corepack pnpm build — passed
• corepack pnpm format:check — pre-existing baseline failure across upstream dev files

Files changed

• src/components/common/BatchBuyModal.tsx — add balance/address validation and submit normalization.
• src/components/common/__tests__/BatchBuyModal.test.tsx — cover issue Add unit tests for the batch transfer modal validating that the total quantity cannot exceed the liquid balance #832 acceptance criteria.
• src/hooks/useWallet.ts — align batch mutation order type with address/quantity contract.

[drips-wave]

@samjay8 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits