feat(openapi): FormCenterSchemaClient 走标准 appCode 网关 fallback，application.yml 出厂 base-host 默认内部网关

src/test/java/com/yunhai/flowcenter/service/AppCodeFormCenterRoutingTest.java

@@ -0,0 +1,41 @@
+package com.yunhai.flowcenter.service;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.sun.net.httpserver.HttpServer;
+import com.yunhai.platform.openapi.core.*;
+import org.junit.jupiter.api.Test;
+import java.net.InetSocketAddress;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+import static org.junit.jupiter.api.Assertions.*;
+
+class AppCodeFormCenterRoutingTest {
+    @Test
+    void realSdkNeedsOnlyGatewayForCatalogAndExactSchema() throws Exception {
+        List<String> paths = new ArrayList<>();
+        HttpServer gateway = HttpServer.create(new InetSocketAddress("127.0.0.1", 0), 0);
+        gateway.createContext("/", exchange -> {
+            String path = exchange.getRequestURI().getPath(); paths.add(path);
+            String data = path.endsWith("/schema")
+                    ? "{\"formUuid\":\"test-form\",\"version\":3,\"groups\":[],\"audience\":[]}"
+                    : "{\"items\":[],\"total\":0}";
+            byte[] bytes = ("{\"code\":0,\"data\":" + data + "}").getBytes(StandardCharsets.UTF_8);
+            exchange.sendResponseHeaders(200, bytes.length);
+            exchange.getResponseBody().write(bytes); exchange.close();
+        });
+        gateway.start();
+        try {
+            OpenApiProperties open = new OpenApiProperties();
+            open.setBaseHost("http://127.0.0.1:" + gateway.getAddress().getPort());
+            YschOpenCall call = new YschOpenCall(new YschCallProperties(), open, new ObjectMapper(), null);
+            assertFalse(call.hasTarget("form-center"));
+            assertEquals(0, new FormCenterCatalogClient(call).listForms(1L, null, null, 1, 20).getTotal());
+            assertEquals(3, new FormCenterSchemaClient(call, new ObjectMapper())
+                    .fetchSchema(1L, "test-form", 3).get("formVersion"));
+            assertEquals(java.util.Arrays.asList("/form-center/oapi/form/forms", "/form-center/oapi/form/schema"), paths);
+        } finally {
+            gateway.stop(0);
+        }
+    }
+}