Update Auto Recharge

Update auto-recharge settings atomically.

• enabled (required) – enable or disable auto-recharge.
• threshold (optional) – the credit balance that triggers a top-up.
• qty (optional) – the amount of credits to add per top-up.

When enabling, the account must have met the minimum spending threshold (fraud-prevention measure). qty must be ≥ $25.

Context (personal vs org) is derived from the API key. Returns the updated settings + eligibility (same shape as GET).