Minimum Wallet Balance Reserve

There's currently no way to hold back a portion of the wallet balance as a refund buffer after a payout is triggered, leaving merchants exposed post-payout.

• No option to reserve a minimum balance after payouts
• Merchants risk having insufficient funds for refunds
• Ask: Add a configurable minimum reserve; payouts only move funds above that threshold
• Example: Min = $1,000 + threshold = $500 → payout triggers at $1,500, paying out $500 only