feat(governance): implement decentralized governance system

[ikemHood]

Pull Request

Description

Add comprehensive governance framework for token-weighted voting:

Core Contract:

• Add Proposal, Vote, ProposalType, ProposalStatus types
• Implement governance config with quorum, voting period, thresholds
• Add storage keys and event definitions

Related Issue(s)

• Closes Build decentralized governance system #57

Type of Change

• ✨ New feature (non-breaking change that adds functionality)

Changes Made

Governance Functions:

• initialize: Set up governance token, admin, and parameters
• create_proposal: Create proposals (requires token threshold)
• cast_vote: Token-weighted voting (For/Against/Abstain)
• finalize_proposal: Determine pass/fail after voting ends
• execute_proposal: Execute passed proposals after delay
• cancel_proposal: Cancel by proposer or admin
• update_config: Admin config updates

Testing

Testing:

• Add MockToken contract for testing
• Add comprehensive test suite (11 tests)
• Test proposal lifecycle, voting, and edge cases

Test Coverage

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed

Testing Steps

 cargo test -p governance-contract

Test Results