feat(webui): add model settings runtime refresh

webui/src/tests/api.test.ts

@@ -1,6 +1,6 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
 
-import { deleteSession, fetchSessionMessages } from "@/lib/api";
+import { deleteSession, fetchSessionMessages, updateSettings } from "@/lib/api";
 
 describe("webui API helpers", () => {
   beforeEach(() => {
@@ -34,4 +34,18 @@ describe("webui API helpers", () => {
       }),
     );
   });
+
+  it("serializes settings updates as a narrow query string", async () => {
+    await updateSettings("tok", {
+      model: "openrouter/test",
+      provider: "openrouter",
+    });
+
+    expect(fetch).toHaveBeenCalledWith(
+      "/api/settings/update?model=openrouter%2Ftest&provider=openrouter",
+      expect.objectContaining({
+        headers: { Authorization: "Bearer tok" },
+      }),
+    );
+  });
 });