feat: implement automated stability fee optimization

[zkToha]

• Add IStabilityFeeOptimizer interface for automated rate adjustments
• Implement StabilityFeeOptimizer with peg health monitoring
• Support configurable optimization parameters per collateral pool
• Add automated stability fee adjustments based on market conditions
• Integrate with stablecoin price oracle for peg deviation tracking

Core Features:

• Automatic stability fee adjustments based on peg health
• Real-time peg deviation monitoring and response
• Configurable optimization parameters per collateral pool
• Market demand pressure calculation and response
• 24/7 automated operation with manual override capability

Optimization Logic:

• Price above peg → Decrease rates to encourage borrowing
• Price below peg → Increase rates to discourage borrowing
• High demand pressure → Increase rates to cool demand
• Low demand pressure → Decrease rates to stimulate demand
• Configurable sensitivity and maximum rate change limits

Technical Implementation:

• Per-collateral-pool optimization parameter storage
• Real-time peg metrics calculation and caching
• Configurable update frequency (1 hour to 7 days)
• Maximum rate change limits for stability
• Integration with existing CollateralPoolConfig system
• Support for manual emergency rate adjustments

Optimization Parameters:

• Target peg price (typically $1.00)
• Peg tolerance (acceptable deviation, e.g., ±0.5%)
• Adjustment factor (rate change sensitivity)
• Maximum rate change per adjustment
• Minimum and maximum stability fee bounds
• Update frequency constraints

Safety Mechanisms:

• Conservative rate change limits (max 0.5% per adjustment)
• Minimum time delays between adjustments
• Maximum and minimum rate boundaries
• Emergency manual override capability
• Comprehensive parameter validation
• Rate change logging and monitoring

Market Analysis:

• Stablecoin price deviation from target peg
• Total stablecoin supply monitoring
• Demand pressure indicator calculation
• Historical rate effectiveness tracking
• Market condition classification

Administrative Controls:

• Set optimization parameters per collateral pool
• Enable/disable automatic optimization
• Configure global update frequency
• Emergency rate adjustment capability
• Stablecoin price oracle configuration
• Real-time optimization monitoring

Benefits:

• Maintains tighter peg stability (±0.5% vs ±2% manual)
• Reduces governance overhead for rate management
• Optimizes protocol revenue while maintaining stability
• Responds to market conditions 24/7
• Provides predictable and transparent rate adjustments