docs(contract): sync TYPES_SYSTEM with types.rs

[Tola-byte]

Pull Request Description

📋 Basic Information

Type of Change

Please select the type of change this PR introduces:

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update
• 🧪 Test addition/update
• 🔧 Refactoring (no functional changes)
• ⚡ Performance improvement
• 🔒 Security fix
• 🎨 UI/UX improvement
• 🚀 Deployment/Infrastructure change

Related Issues

Closes #437
Fixes #437
Related to #437

Priority Level

• 🔴 Critical (blocking other development)
• 🟡 High (significant impact)
• 🟢 Medium (moderate impact)
• 🔵 Low (minor improvement)

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📝 Detailed Description

What does this PR do?

• Syncs docs/contracts/TYPES_SYSTEM.md with the actual #[contracttype] definitions in contracts/predictify-hybrid/src/types.rs.
• Fixes a validation gap in Market::validate by validating fallback_oracle_config whenever has_fallback == true.
• Adds regression tests to enforce the fallback validation behavior.

Why is this change needed?

• The documentation had drifted from code, making integration/audit review harder.
• A malformed fallback oracle config could pass Market::validate previously, creating a correctness/security risk at resolution time.
• This PR restores type-documentation parity and enforces stronger upfront validation invariants.

How was this tested?

• Added unit tests in types.rs:
  • market_validate_rejects_invalid_fallback_when_enabled
  • market_validate_allows_no_fallback_sentinel_path
• Ran full crate tests locally.

Alternative Solutions Considered

• Leaving fallback validation to downstream oracle/resolution flows only.
  Rejected because early validation is safer, simpler, and easier to reason about.

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🏗️ Smart Contract Specific

Contract Changes

Please check all that apply:

• Core contract logic modified
• Oracle integration changes (Pyth/Reflector)
• New functions added
• Existing functions modified
• Storage structure changes
• Events added/modified
• Error handling improved
• Gas optimization
• Access control changes
• Admin functions modified
• Fee structure changes

Oracle Integration

• Pyth oracle integration affected
• Reflector oracle integration affected
• Oracle configuration changes
• Price feed handling modified
• Oracle fallback mechanisms
• Price validation logic

Market Resolution Logic

• Hybrid resolution algorithm changed
• Dispute mechanism modified
• Fee structure updated
• Voting mechanism changes
• Community weight calculation
• Oracle weight calculation

Security Considerations

• Access control reviewed
• Reentrancy protection
• Input validation
• Overflow/underflow protection
• Oracle manipulation protection

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🧪 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
• Gas usage optimized
• Cross-contract interactions tested

Test Results

cargo +stable test -p predictify-hybrid

test result: ok. 272 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

Manual Testing Steps

1. Created a market with valid primary oracle and invalid fallback oracle while has_fallback=true; confirmed Market::validate returns Error::InvalidOracleConfig.
2. Created a market with fallback_oracle_config=None; confirmed sentinel path still validates.
3. Ran full crate test suite and confirmed all tests pass.

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📚 Documentation

Documentation Updates

• README updated
• Code comments added/updated
• API documentation updated
• Examples updated
• Deployment instructions updated
• Contributing guidelines updated
• Architecture documentation updated

Breaking Changes

Breaking Changes:

• None

Migration Guide:

• No migration required.

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🔍 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

Performance Impact

• Gas Usage: Negligible; one extra fallback config validation branch in Market::validate.
• Storage Impact: None.
• Computational Complexity: Constant-time additional validation when fallback is enabled.

Security Review

• No obvious security vulnerabilities
• Access controls properly implemented
• Input validation in place
• Oracle data properly validated
• No sensitive data exposed

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🚀 Deployment & Integration

Deployment Notes

• Network: N/A (contract source update)
• Contract Address: N/A
• Migration Required: No
• Special Instructions: None

Integration Points

• Frontend integration considered
• API changes documented
• Backward compatibility maintained
• Third-party integrations updated

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📊 Impact Assessment

User Impact

• End Users: Reduced risk of markets created with invalid fallback oracle config.
• Developers: Accurate TYPES_SYSTEM.md now matches code 1:1 for integrator use.
• Admins: Earlier failure on invalid fallback config improves operational safety.

Business Impact

• Revenue: Neutral.
• User Experience: Positive for reliability and predictability.
• Technical Debt: Reduced documentation drift and validation ambiguity.

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✅ 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

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📸 Screenshots (if applicable)

N/A

🔗 Additional Resources

• Design Document: N/A
• Technical Spec: docs/contracts/TYPES_SYSTEM.md
• Related Discussion: Issue Types documentation sync #437
• External Documentation: N/A

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💬 Notes for Reviewers

Please pay special attention to:

• Market::validate fallback validation branch correctness and expected error behavior.
• Documentation parity between docs/contracts/TYPES_SYSTEM.md and types.rs contract types.

Questions for reviewers:

• Should we additionally validate non-empty feed_id in OracleConfig::validate in a follow-up PR?

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Thank you for your contribution to Predictify! 🚀

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