Fix/staking env bigint parsing

[edilsonGoncalvesR]

Summary

Tasks for protocol staking currently convert numeric environment variables with
parseInt(...) and then wrap them in BigInt(...). Since parseInt returns a
JavaScript Number, this may lose precision for large 256-bit values (e.g. token
amounts in 18 decimals).

This PR updates the staking tasks to convert env vars directly to BigInt
using the string returned by getRequiredEnvVar.

Changes

• protocol-contracts/staking/tasks/setRewardRate.ts:

  • Use BigInt(getRequiredEnvVar(...)) for PROTOCOL_STAKING_COPRO_REWARD_RATE
    and PROTOCOL_STAKING_KMS_REWARD_RATE.

• protocol-contracts/staking/tasks/deposit.ts:

  • Use BigInt(getRequiredEnvVar(...)) for
    OPERATOR_STAKING_COPRO_INITIAL_DEPOSIT_ASSETS_* and
    OPERATOR_STAKING_KMS_INITIAL_DEPOSIT_ASSETS_*.

• protocol-contracts/staking/tasks/setOwnerFee.ts:

  • Use BigInt(getRequiredEnvVar(...)) for
    OPERATOR_REWARDER_COPRO_OWNER_FEE_* and
    OPERATOR_REWARDER_KMS_OWNER_FEE_*.

Rationale

• getRequiredEnvVar already returns a string, which is a valid input to BigInt.
• Avoids going through Number and the associated precision limits.
• Safer for large values expressed in smallest token units (18 decimals).

Testing

• Type-checks and builds the staking tasks with:
  • cd protocol-contracts/staking
  • npm test / pnpm test (as used in the repo)
• Manually verified example Hardhat commands with small values still work as expected.

[cla-bot]

Thank you for your pull request. We require contributors to sign our Contributor License Agreement / Terms and Conditions, and we don't seem to have the users @edilsonGoncalvesR on file. In order for us to review and merge your code, please sign:

• For individual contribution: our CLA
• for Bounty submission, if you are an individual: our T&C
• for Bounty submission, if you are a company: our T&C
  to get yourself added.

If you already signed one of this document, just wait to be added to the bot config.