reeplace

[Nabeelahh]

closes #28

Summary

This PR addresses the inconsistent and verbose admin authorization pattern across all six contracts by introducing a shared helper and standardized error handling. The changes eliminate boilerplate, ensure consistent error messages, and improve maintainability.

Changes

• Added contracts/common/src/auth.rs with require_admin() helper
• Added contracts/common/src/errors.rs with ContractError enum
• Migrated all six contracts to use the new helper
• Standardized error handling with proper Soroban error codes
• Added comprehensive tests for edge cases

Test Plan

• All existing contract tests pass
• New helper unit tests added:
  • test_require_admin_success()
  • test_require_admin_failure()
  • test_require_admin_uninitialized()
  • test_error_encoding()
• Integration tests verify consistent error behavior
• grep -r "Unauthorized" contracts/*/src/lib.rs returns only references in error enum

Checklist

• cargo fmt --check passes
• cargo clippy -D warnings passes
• cargo test passes

Impact on All Contracts

1. Pool Factory: Admin initialization and management
2. Pool Router: Protocol admin functions
3. Pool: Fee and admin parameter updates
4. Fee Distributor: Withdrawal and configuration
5. Staking: Reward rate and admin controls
6. Token: Mint/burn admin permissions

Migration Complete

• ✅ All six contracts updated to use require_admin()
• ✅ Inconsistent error messages replaced with ContractError::Unauthorized
• ✅ expect() replaced with proper error handling
• ✅ Tests updated to expect standardized error codes