Add comment for prepaid workspace recharge logic

Added a clarifying comment explaining the recharge process for prepaid workspaces, noting that limits should be reset even if no payment is due. This improves code readability and understanding of billing logic.

Author: talyguryn

workers/paymaster/src/index.ts

@@ -226,6 +226,10 @@ export default class PaymasterWorker extends Worker {
      */
     if (!isTimeToPay) {
       /**
+       * [USED FOR PREPAID WORKSPACES]
+       * "Recharge" — to reset limits for the new billing period (month).
+       *  It should be done even for prepaid workspaces that do not need to pay anything today.
+       *
        * If it is time to recharge workspace limits, but not time to pay
        * Start new month - recharge billing period events count and update last charge date
        */