Your monthly allowance: limit, used, remaining, percent, and what it buys per model

The allowance is BILLED SECONDS, and each model spends it at its own rate: a second of Kokoro costs 1.5, a second of XTTS costs 3. So there is one percentUsed, and byModel[].remainingSeconds says how much audio the remainder buys in each model — those are ALTERNATIVES drawn from the same pot, not separate budgets.

limitSeconds and remainingSeconds are null when the account is unmetered. Exceeding the allowance answers 402 QUOTA_EXCEEDED — deliberately not 429, because waiting does not help until resetsAt.

The aggregate numbers ride on every synthesis response as X-Ditto-Quota-* headers, so an integration can watch its own headroom without polling this.