feat(gate): buildSchemaLinkingRequest descriptor builder

harness/.pi/extensions/gate/__tests__/builders.test.js

@@ -15,6 +15,7 @@ const {
   buildArtifactGate,
   buildInfoRequest,
   buildFreetextRequest,
+  buildSchemaLinkingRequest,
   withChildLinkage,
 } = require("../builders.js");
 
@@ -118,6 +119,17 @@ test("freetext request carries a title and no options", () => {
   assert.deepEqual(result.reserved, ["back", "exit", "other"]);
 });
 
+test("buildSchemaLinkingRequest carries tables + reserved", () => {
+  const out = buildSchemaLinkingRequest({
+    id: "u7", phase: "F4", title: "F4 — Schema linking",
+    tables: [{ id: "t1", name: "dim_patient", kind: "promote", columns: [] }],
+  });
+  assert.equal(out.widget, "schema-linking");
+  assert.equal(out.id, "u7");
+  assert.equal(out.tables.length, 1);
+  assert.deepEqual(out.reserved, ["back", "exit", "other"]);
+});
+
 test("withChildLinkage sets option.opens and returns the option", () => {
   const child = { widget: "freetext", title: "Motivazione del rifiuto" };
   const option = withChildLinkage({ id: "reject", label: "Rifiuta" }, child);