Module vesting 

Fren Pet Stake-to-Play (S2P): staked DOJO refunds linearly over 30 days (per slot).

Functions

push_stake_tranche

Append a new vesting tranche. Returns Err if all slots are full.

stake_apply_withdraw

Apply a withdrawal against tranches in order (FIFO). Clears tranches when fully withdrawn.

stake_claimable_from_tranche

Unlocked minus already withdrawn from this tranche.

stake_total_claimable

stake_unlocked_amount

Linear unlocked amount from start_slot over STAKE_VESTING_SLOTS.