Add Rz Coin utility store

scripts/autoload/exam_simulation_service.gd

@@ -8,6 +8,7 @@ signal state_changed
 signal request_failed(message: String)
 signal outcome_changed
 signal history_changed
+signal exam_token_required
 
 var api_url := DEFAULT_API_URL
 var outcome_api_url := "https://us3q.ranaze.com/api/step3-outcomes"
@@ -152,6 +153,14 @@ func _on_request_completed(result: int, response_code: int, _headers: PackedStri
 		AuthState.handle_unauthorized(request_access_token)
 	if result != HTTPRequest.RESULT_SUCCESS or response_code < 200 or response_code >= 300:
 		var server_message := body.get_string_from_utf8().strip_edges()
+		var error_parsed: Variant = JSON.parse_string(server_message)
+		if typeof(error_parsed) == TYPE_DICTIONARY:
+			var credit_status: Variant = error_parsed.get("credits", {})
+			if typeof(credit_status) == TYPE_DICTIONARY:
+				CreditsService.apply_status(credit_status)
+			if str(error_parsed.get("code", "")) == "exam_token_required":
+				exam_token_required.emit()
+			server_message = str(error_parsed.get("message", server_message))
 		if server_message.length() > 240:
 			server_message = server_message.left(240)
 		var message := "Simulation request failed with status %d." % response_code