[sontrinh16]

Summary

Address medium-severity audit findings related to state consistency, validation, query safety, and parameter error handling.

Changes

• Prevent partial multi-staking state updates during redelegation and undelegation:
  • Persist source and destination locks only after stakingMsgServer.BeginRedelegate succeeds.
  • Persist lock and unlock records only after staking undelegation succeeds.
  • Preserve existing lock state when staking returns an error or panics in a non-cached context.
• Strengthen MultiStakingCoin.Validate:
  • Reject zero and negative amounts.
  • Reject invalid denominations.
  • Continue rejecting zero and negative bond weights.
• Validate unlocking coins before converting unbonded amounts, preventing invalid bond weights from reaching division logic.
• Reject nil requests in the validators gRPC query.
• Update GetParams to return errors for:
  • Store read failures.
  • Missing parameter data.
  • Parameter decoding failures.
• Update the expected staking keeper interface and all affected callers for the new GetParams signature.

Testing

Added regression coverage for:

• Redelegation failures preserving source and destination lock state.
• Undelegation failures preserving lock state and avoiding unlock creation.
• Valid, zero, and negative multi-staking amounts.
• Valid and invalid denominations.
• Missing, malformed, and unreadable parameter data.

[hieuvubk]

lgtm!
Let take a final review before merge. New commit pushed 7400cea.

It fix CancelUnbonding rounding error with bond_weight < 1. Currently we all use weight 1 => not exploited but worth to fix

[hieuvubk]

cc @sontrinh16