checkpoint ISAC registries and system monitoring

docs/architecture.md

@@ -182,6 +182,15 @@ and historical analysis should eventually use a dedicated external telemetry
 system. This surface deliberately omits secrets, environment-variable values,
 and full database paths.
 
+The same surface reports remove.bg paid credits and free API calls as separate
+capacity pools. The scheduler reconciles the account balance no more often than
+the configured interval, while successful image processing applies the
+provider's `X-Credits-Charged` value to the persisted estimate. Warning and
+critical transitions create one alert episode with a unique delivery for each
+active Administrator. A later critical transition may alert again; repeated
+scheduler runs within the same episode do not. Provider errors preserve the
+last known balance and never expose the API key or raw response body.
+
 # Weapon-owned exotic talents
 
 Standard weapon talent pools remain globally reusable and classified by Talent