Enhanced Rewards Calculation

[joeljkrb]

Summary
Addresses user feedback regarding inaccurate reward forecasts (5-10% overestimation). Implements validator-specific performance calculations, conservative adjustments for real-world factors.

Root Cause Analysis

• Reward calculations used simplified network averages instead of actual nominated validator performance
• Missing era points performance factor in calculations
• Commission rates applied as blanket percentage rather than validator-specific rates
• No adjustment for real-world factors (era timing, validator downtime, network effects)

Solution Implementation
New useEnhancedRewardRate Hook:

• Calculates era points performance multiplier based on nominated validators vs network average
• Uses actual commission rates from user's nominated validators
• Applies 15% conservative adjustment factor to account for real-world conditions
• Maintains backward compatibility with existing calculation methods

Key Improvements:

• Era points factor: Accounts for validator performance variance
• Validator-specific commissions: Replaces network averages with actual rates
• Conservative adjustment: 15% reduction aligned with historical performance data
• Performance optimisation: Memoized calculations prevent excessive re-computation

[rossbulat]

The average reward rate calculation using node data only is just a fallback for networks who do not support the Staking API, I don't think it is worth introducing this much boilerplate for a feature that is only a fallback. The real ARR calculations are done on the Staking API side. It is probably worth revisiting the rate on the API side - but only then tweaking it with fixes rather than a new integration