feat(tri27): TRI-27 Staking Module

[gHashTag]

Sub-Issue #438: TRI-27 Staking Module

Files: src/tri27/staking.zig (NEW, ~400 LOC)

Tasks:

• Create spec/staking.tri
• Generate staking.zig via tri gen
• Define StakingState:
  • total_staked: u128
  • stakers: AutoHashMap([32]u8 -> StakeInfo)
  • reward_pool: u128
  • apy: f64
• Implement functions:
  • stakeTokens(amount, lock_period)
  • unstakeTokens()
  • calculateReward(compute_units) -> u128
  • distributeRewards(epoch)
• Add Coptic mapping:
  • t21: Total staked
  • t22: Current APY
• Add slashing:
  • Manipulation: -50% stake
  • Theft: -100% stake

Parent: #435