Feat: implement Upgradeable Contract pattern for Predictify

[emarc99]

Pull Request Description

📋 Basic Information

Adds comprehensive upgrade functionality with proposal workflows, version compatibility validation, rollback support, and complete audit trails.

Type of Change

Please select the type of change this PR introduces:

• ✨ New feature (non-breaking change which adds functionality)
• 🧪 Test addition/update

Related Issues

• Closes Create Upgradeable Contract Pattern with Validation and Rollback #90

Priority Level

• 🔴 Critical (blocking other development)
• 🟡 High (significant impact)

---

📝 Detailed Description

What does this PR do?

This PR implements a comprehensive upgrade management system for the Predictify Hybrid Soroban smart contract. It adds the ability to safely upgrade contract WASM code while maintaining state, with built-in safeguards including:

• Proposal-based workflow: Upgrades must be proposed, validated, and approved before execution
• Version compatibility checking: Automatic detection of breaking changes using semantic versioning
• Rollback capability: Stores previous WASM hashes to enable quick rollback if issues occur
• Audit trail: Complete history of all upgrades with timestamps, success/failure status, and initiator tracking
• Safety validations: Customizable pre-upgrade checks to prevent dangerous upgrades
• Statistics tracking: Analytics on upgrade success rates, failure patterns, and timing

Why is this change needed?

Smart contracts need upgradeability to:

1. Fix critical bugs discovered in production without losing state or changing contract address
2. Add new features as the protocol evolves
3. Improve gas efficiency through optimizations
4. Maintain security by patching vulnerabilities quickly

How was this tested?

Comprehensive Test Suite: 24 tests covering all scenarios (100% pass rate)

Test Categories:

• Proposal Lifecycle (7 tests): Creation, approval, execution, validation workflows
• Compatibility Validation (5 tests): Breaking changes, migration requirements, safety checks
• Version Tracking (4 tests): Version retrieval, history management, statistics
• Integration (8 tests): Full upgrade workflows including rollback scenarios

Alternative Solutions Considered

---

🏗️ Smart Contract Specific

Key Features

• Safe contract upgrades via env.deployer().update_current_contract_wasm()
• Upgrade proposal system with approval workflows
• Semantic version compatibility validation
• Automatic rollback support with wasm hash tracking
• Complete upgrade history and statistics
• Safety validation framework
• Admin authorization for all operations

API

• 8 new public contract methods:
• upgrade_contract() - Perform upgrades
• rollback_upgrade() - Rollback to previous version
• get_contract_version() - Get current version
• check_upgrade_available() - Check pending upgrades
• get_upgrade_history() - View upgrade history
• get_upgrade_statistics() - Upgrade metrics
• validate_upgrade_compatibility() - Version validation
• test_upgrade_safety() - Pre-upgrade safety checks

Testing

• 24/24 tests passing (100%)
• Complete coverage of upgrade scenarios
• Integration tests with full workflows
• Proper contract registration and storage persistence

Contract Changes

• Core contract logic modified
• New functions added
• Existing functions modified
• Storage structure changes
• Events added/modified
• Error handling improved
• Gas optimization

---

🧪 Testing

Test Coverage

• Unit tests added/updated
• Integration tests added/updated
• All tests passing locally
• Manual testing completed
• Oracle integration tested
• Edge cases covered
• Error conditions tested

Test Results

cargo test
# test result: ok. 24 passed; 0 failed; 0 ignored; 0 measured; 202 filtered out; finished in 6.40s

---

🔍 Code Quality

Code Review Checklist

• Code follows Rust/Soroban best practices
• Self-review completed
• No unnecessary code duplication
• Error handling is appropriate
• Logging/monitoring added where needed
• Security considerations addressed
• Performance implications considered
• Code is readable and well-commented
• Variable names are descriptive
• Functions are focused and small

---

✅ Final Checklist

Pre-Submission

• Code follows Rust/Soroban best practices
• All CI checks passing
• No breaking changes (or breaking changes are documented)
• Ready for review
• PR description is complete and accurate
• All required sections filled out
• Test results included
• Documentation updated

Review Readiness

• Self-review completed
• Code is clean and well-formatted
• Commit messages are clear and descriptive
• Branch is up to date with main
• No merge conflicts

---

📸 Screenshots (if applicable)

Thank you for your contribution to Predictify! 🚀

[greatest0fallt1me]

LGTM! @emarc99