fix(sites): keep the legacy contact name when an update sends no contacts

src/domain/locations/mappers/location-mapper.ts

@@ -235,7 +235,8 @@ export function mapLocationToBackend(location: unknown): Record<string, unknown>
     state: item.state ?? "",
     zipCode: item.zipCode ?? "",
     phone: typeof item.sitePhone === "string" ? item.sitePhone.trim() : "",
-    contact: mainContact ? mainContact.name : "",
+    // A caller without a contacts list (e.g. address-only sync) keeps the stored legacy name.
+    contact: mainContact ? mainContact.name : readString(item, "contact").trim(),
     contactEmail: typeof item.contactEmail === "string" ? item.contactEmail.trim() : "",
     accountId: item.accountId ?? "",
     contacts,

src/test/domain/locations/mappers/location-mapper.test.ts

@@ -107,6 +107,21 @@ describe("mapLocationToBackend site payload", () => {
     expect(bare).not.toHaveProperty("notes");
     expect(full).toMatchObject({ status: "Active", title: "Dallas DC", notes: "Gate code 1234" });
   });
+
+  it("keeps the legacy contact name when the caller sends no contacts list", () => {
+    const addressOnly = mapLocationToBackend({
+      name: "DAL1",
+      address: "3811 Distribution Dr",
+      contact: "Jane Doe",
+    });
+    const withContacts = mapLocationToBackend({
+      contact: "Jane Doe",
+      contacts: [{ name: "Bob", phone: "(421) 433-0033" }],
+    });
+
+    expect(addressOnly.contact).toBe("Jane Doe");
+    expect(withContacts.contact).toBe("Bob");
+  });
 });
 
 describe("mapLocation site fields", () => {