fix: createAuthHeaders return shape

server.js

@@ -101,9 +101,12 @@ app.use(
     new HTTPFacilitatorClient({
       url: FACILITATOR_URL,
       ...(FACILITATOR_API_KEY && {
-        createAuthHeaders: async () => ({
-          headers: { Authorization: `Bearer ${FACILITATOR_API_KEY}` },
-        }),
+        // The lib calls this for each operation ("verify"/"settle"/"supported")
+        // and indexes into the returned object by op name.
+        createAuthHeaders: async () => {
+          const auth = { Authorization: `Bearer ${FACILITATOR_API_KEY}` };
+          return { verify: auth, settle: auth, supported: auth };
+        },
       }),
     }),
     [{ network: NETWORK, server: new ExactStellarScheme() }],