Rewrite trader service for V4 P0

src/main/java/com/quantai/trader/domain/FeedbackValidator.java

@@ -0,0 +1,14 @@
+package com.quantai.trader.domain;
+
+import com.quantai.trader.enums.TraderErrorCode;
+import org.springframework.stereotype.Component;
+
+@Component
+public class FeedbackValidator {
+    public void validateP0(TraderAppFeedback feedback) {
+        if (!feedback.feedbackSource().p0Allowed() || feedback.realFill()) {
+            throw new TraderException(TraderErrorCode.TRADER_FEEDBACK_INVALID,
+                    "P0 rejects PAPER_APP/REAL_APP and any realFill feedback");
+        }
+    }
+}