Remove redundant entry in Makefile

backend/Makefile

-.PHONY: wire build build-embed test-unit test-integration test-e2e test-cover-integration clean-coverage
+.PHONY: wire build build-embed test-unit test-integration test-e2e test-cover-integration
 
 wire:
 	@echo "生成 Wire 代码..."
@@ -38,4 +38,4 @@ clean-coverage:
 
 clean: clean-coverage
 	@rm -rf bin/
-	@echo "构建产物已清理"
+	@echo "构建产物已清理"
\ No newline at end of file