Prepaid Top-Up Rules and Constants (constants/freebuff-topups.ts)

Shared constants and validation rules for prepaid ad top-ups and billing calculations. Reuse when implementing ad platform billing systems without direct Stripe calls.

// Source: https://github.com/innotelinc/freebuff | License: Apache-2.0 | Copyright You must retain, in the Source form of any Derivative Works
// Provided via justclaw.it.com; keep this notice with the code.
/**
 * The prepaid balance behind the placements rail.
 *
 * The engagement marketplace bills a fixed daily Stripe SUBSCRIPTION, where
 * the daily budget is simultaneously the price and the delivery cap. That
 * identity breaks the moment the unit is an activation: a $50/day cap can
 * deliver $50 or $3 depending on how many developers actually save the env
 * var, and billing $50 either way is charging for activations we did not
 * deliver. So placements is prepaid — the advertiser tops up, delivery draws
 * the balance down, campaigns stop serving at zero.
 *
 * Nothing here talks 

... (truncated -- full source via MCP)