Design new reward-history view

[ECWireless]

• Reward history should explain how rewards were determined, not just show the final amount.
• Research/design should consider showing per-round or recent-round history for:
  • fee share
  • stake share
  • MFS-eligible reward share / reward cap
  • validator RewardMultiplier
  • final LPT rewards earned
  • delegator APY / realized return where appropriate
• Make it clear when rewards were limited by:
  • insufficient stake relative to fees
  • lower validator scores
  • the 7-round reward delay
• The view should help delegators and node operators understand both:
  • why they earned what they earned
  • what would need to change to improve future rewards