feat: implement comprehensive validation system with security checks …

[Samuel1-ona]

This issue cloese #69

• Implement comprehensive input validation for all contract parameters
• Ensure all validation tests pass (88/88 tests passing)
• Provide clear error messages

1. Enhanced Validation System (src/validation.rs)

New Validation Error Types

pub enum ValidationError {
    // Existing errors...
    StringTooLong,
    StringTooShort,
    NumberOutOfRange,
    InvalidAddressFormat,
    TimestampOutOfBounds,
    ArrayTooLarge,
    ArrayTooSmall,
    InvalidQuestionFormat,
    InvalidOutcomeFormat,
}

Comprehensive Input Validation

• String Length Validation: Enforces min/max length limits for all string inputs
• Numeric Range Validation: Validates all numeric parameters within specified ranges
• Address Format Validation: Enhanced address validation with security checks
• Timestamp Bounds Validation: Ensures timestamps are within valid ranges
• Array Size Validation: Validates array sizes with configurable limits
• Question Format Validation: Specific validation for market questions
• Outcome Format Validation: Specific validation for market outcomes

2. Comprehensive Test Suite (src/validation_tests.rs)

Test Coverage

• 20 comprehensive validation tests covering all validation scenarios
• Unit tests for individual validation functions
• Integration tests for validation workflows
• Edge case testing for boundary conditions
• Performance testing for validation efficiency
• Error message testing for clear user feedback

Test Categories

1. String length validation tests
2. Numeric range validation tests
3. Address format validation tests
4. Timestamp bounds validation tests
5. Array size validation tests
6. Question format validation tests
7. Outcome format validation tests
8. Comprehensive input validation tests
9. Market creation validation tests
10. Vote validation tests
11. Validation error conversion tests
12. Validation result tests
13. Fee validation tests
14. Oracle validation tests
15. Dispute validation tests
16. Validation error handler tests
17. Validation documentation tests
18. Edge case tests
19. Performance tests
20. Error message tests

3. Module Integration (src/lib.rs)

• Added validation_tests module to the main library
• Ensured proper module visibility and exports
• Maintained backward compatibility with existing code

Input Validation

• String Length Limits: Prevents buffer overflow and memory issues
• Numeric Range Checks: Ensures parameters are within safe bounds
• Address Validation: Validates all address inputs for format and security
• Timestamp Validation: Prevents time-based attacks and invalid scheduling
• Array Size Limits: Prevents DoS attacks through oversized arrays

[Samuel1-ona]

@greatest0fallt1me, please review my PR.

[greatest0fallt1me]

@Samuel1-ona can you please resolve the conflicts