Refactor: Centralize Fee Management System in Predictify Hybrid Contract

[1nonlypiece]

This PR implements a comprehensive refactor of the fee management system in the predictify-hybrid contract, moving from scattered fee logic across multiple files to a dedicated, modular fee management system.

Closes #109

Changes Made

🏗️ New Fee Management Architecture

• Created contracts/predictify-hybrid/src/fees.rs - Centralized fee management module
• Implemented comprehensive fee types and structures:
  • FeeConfig - Configurable fee parameters
  • FeeAnalytics - Fee collection statistics and metrics
  • FeeBreakdown - Detailed fee calculation breakdowns
  • FeeValidation - Fee validation results and error reporting

🔧 Core Fee Management Components

FeeManager - Main fee orchestration

• collect_fees() - Centralized fee collection logic
• process_creation_fee() - Market creation fee handling
• get_fee_analytics() - Fee statistics and reporting
• update_fee_config() - Dynamic fee configuration updates

FeeCalculator - Fee computation engine

• calculate_platform_fee() - Platform fee calculations
• calculate_user_payout_after_fees() - User payout computations
• calculate_fee_breakdown() - Detailed fee breakdowns
• calculate_dynamic_fee() - Volume-based fee adjustments

FeeValidator - Validation and safety checks

• validate_admin_permissions() - Admin authorization
• validate_fee_amount() - Fee amount bounds checking
• validate_market_for_fee_collection() - Market eligibility validation
• validate_fee_config() - Configuration integrity checks

FeeUtils - Utility functions

• can_collect_fees() - Quick eligibility checks
• get_fee_eligibility() - Detailed eligibility with reasons

FeeConfigManager - Configuration management

• store_fee_config() - Configuration persistence
• get_fee_config() - Configuration retrieval
• reset_to_defaults() - Default configuration restoration

FeeAnalytics - Analytics and reporting

• calculate_analytics() - Overall fee statistics
• get_market_fee_stats() - Per-market fee metrics
• calculate_fee_efficiency() - Fee collection efficiency

🔄 Integration Updates

Updated lib.rs

• Added fees module integration
• Exposed new fee-related contract methods:
  • collect_fees()
  • get_fee_analytics()
  • get_fee_config()
  • update_fee_config()
  • validate_market_fees()
• Replaced direct fee logic with calls to new fee management system

Updated markets.rs

• Delegated fee logic to new fees module
• Deprecated old fee-related functions
• Maintained backward compatibility

Updated voting.rs

• Delegated fee logic to new fees module
• Deprecated old fee-related functions
• Maintained backward compatibility

🧪 Comprehensive Test Suite

• Added 20+ new fee management tests in test.rs
• Test coverage includes:
  • Fee collection workflows
  • Fee calculation accuracy
  • Validation logic
  • Configuration management
  • Analytics computation
  • Error handling scenarios
  • Dynamic fee adjustments
  • Admin permission validation

🔒 Safety and Validation Features

• Fee safety checks - Prevents invalid fee operations
• Admin permission validation - Ensures only authorized users can modify fees
• Configuration validation - Validates fee parameter integrity
• Market eligibility checks - Ensures proper market state for fee collection
• Error handling - Comprehensive error reporting and recovery

⚙️ Configuration Management

• Dynamic fee configuration - Runtime fee parameter updates
• Default configuration - Safe fallback values
• Configuration persistence - Persistent fee settings
• Validation rules - Ensures configuration integrity

Technical Details

Fee Configuration Parameters

• platform_fee_percentage - Platform fee percentage (default: 2%)
• creation_fee - Market creation fee (default: 10 XLM)
• min_fee_amount - Minimum fee amount (default: 0.1 XLM)
• max_fee_amount - Maximum fee amount (default: 100 XLM)
• collection_threshold - Minimum stakes for fee collection (default: 10 XLM)
• fees_enabled - Global fee enable/disable flag

Dynamic Fee Adjustments

• Volume-based discounts - Larger markets get fee reductions
• Configurable thresholds - Adjustable volume breakpoints
• Percentage-based calculations - Precise fee computations

Analytics and Reporting

• Total fees collected - Aggregate fee statistics
• Markets with fees - Fee collection coverage
• Average fee per market - Performance metrics
• Fee efficiency tracking - Collection success rates

Benefits

✅ Modularity - Clean separation of fee concerns
✅ Maintainability - Centralized fee logic for easier updates
✅ Testability - Comprehensive test coverage for all fee operations
✅ Safety - Multiple validation layers and error handling
✅ Flexibility - Dynamic configuration and runtime updates
✅ Analytics - Detailed fee reporting and metrics
✅ Backward Compatibility - Existing functionality preserved

Testing

• Build Status: ✅ All compilation errors resolved
• Test Coverage: 20+ new fee management tests added
• Integration: All existing functionality preserved
• Validation: Comprehensive error handling and edge cases covered

Breaking Changes

None - This refactor maintains full backward compatibility while adding new functionality.

Migration Notes

No migration required - existing fee collection logic continues to work as before, with enhanced capabilities available through new methods.

[greatest0fallt1me]

Thanks for the PR @1nonlypiece