Add an "Add hints" form on the admin user card that additively tops up a
player's hint wallet (1-100 per grant). The grant is raise-only by
construction (an additive UPDATE never lowers the balance) and stays correct
under a concurrent in-game spend; a per-grant cap bounds a fat-finger, since
the console can never reduce a wallet.
The in-game hint policy is unchanged and already correct: a game offers the
per-seat allowance plus the wallet, spending the allowance first and the
wallet only after (covered by TestHintPolicy).
Ilia Denisov