safe commit

[Glam26]

Summary
Here's what was changed for the GrantFox FWC26 campaign (Closes #917):
contracts/settlement/src/lib.rs

• Replaced daily.amount = daily.amount.saturating_add(amount) with daily.amount = daily.amount.checked_add(amount).ok_or(SettlementError::DailyWithdrawCapExceeded)? in withdraw_developer_balance
• This was the only remaining non-checked arithmetic in the settlement contract. Previously, if the daily withdrawal accumulator overflowed i128 , it would silently saturate to i128::MAX . Now it fails loudly with DailyWithdrawCapExceeded .
  contracts/settlement/src/test_overflow_safe_math.rs
• Added poke_withdrawal_today helper to seed the daily withdrawal state in tests
• Added withdraw_daily_amount_overflow_raises_error test: seeds the daily accumulator at i128::MAX - 1 , sets cap to 0 (unlimited), then withdraws 1 micro-unit — verifies the overflow is caught
  API/Visible changes
  None. The function signatures, event schemas, and error codes remain unchanged. The DailyWithdrawCapExceeded error (code 13) was already documented and is now reused for this overflow case. This is a strict safety improvement — silent data corruption is replaced with a deterministic revert.
  Pre-existing issue
  The Cargo.lock has merge conflicts and duplicate entries that prevent compilation, but these are pre-existing and unrelated to this change.

closes #857

[drips-wave]

@Glam26 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