test(frontend): cover NewSessionDialog model degradation + invalidate sessions on resume

- Add NewSessionDialog.test.tsx covering §9 graceful degradation:
  empty models -> free-text input; non-empty models -> dropdown; plus a
  createSession body-keys assertion
- Normalize model entries to {value,label} so object-shaped models
  ({provider,id}) render correctly in the dropdown (was assuming strings)
- NavSessions: invalidate the ["sessions"] query after a successful
  resumeSession so the list/status refreshes immediately

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/shell/NavSessions.tsx

@@ -1,5 +1,5 @@
 // frontend/src/shell/NavSessions.tsx
-import { useQuery } from "@tanstack/react-query";
+import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { listSessions } from "../api/sessions";
 import { resumeSession } from "../api/sessions";
 import type { SessionSummary } from "../api/types";
@@ -10,6 +10,7 @@ interface Props {
 }
 
 export function NavSessions({ activeSessionId, onSessionSelect }: Props) {
+  const queryClient = useQueryClient();
   const { data: sessions = [] } = useQuery<SessionSummary[]>({
     queryKey: ["sessions"],
     queryFn: listSessions,
@@ -18,6 +19,7 @@ export function NavSessions({ activeSessionId, onSessionSelect }: Props) {
 
   async function handleClick(id: string) {
     await resumeSession(id);
+    queryClient.invalidateQueries({ queryKey: ["sessions"] });
     onSessionSelect(id);
   }
 

frontend/src/shell/NewSessionDialog.test.tsx

@@ -0,0 +1,82 @@
+// frontend/src/shell/NewSessionDialog.test.tsx
+import { render, screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { http, HttpResponse } from "msw";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { server } from "../test/msw";
+import { NewSessionDialog } from "./NewSessionDialog";
+
+function renderDialog() {
+  const onCreated = vi.fn();
+  const client = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+  render(
+    <QueryClientProvider client={client}>
+      <NewSessionDialog onCreated={onCreated} />
+    </QueryClientProvider>,
+  );
+  return { onCreated };
+}
+
+beforeEach(() => {
+  server.use(
+    http.get("http://localhost:8787/workspaces", () =>
+      HttpResponse.json([{ name: "default", file: "default.db" }]),
+    ),
+    http.post("http://localhost:8787/sessions", () =>
+      HttpResponse.json({ id: "s1" }),
+    ),
+  );
+});
+
+test("§9 degradation: empty models -> model field is a FREE-TEXT input, not a select", async () => {
+  server.use(
+    http.get("http://localhost:8787/models", () => HttpResponse.json({ models: [] })),
+  );
+  renderDialog();
+  await userEvent.click(screen.getByRole("button", { name: /nuova/i }));
+
+  // Free-text model input present; no model dropdown.
+  const freetext = await screen.findByTestId("model-freetext");
+  expect(freetext.tagName).toBe("INPUT");
+  // The only <select> in the dialog is the workspace one (id nsd-workspace).
+  expect(screen.queryByRole("combobox", { name: /modello/i })).not.toBeInTheDocument();
+});
+
+test("§9: non-empty models -> model field is a dropdown (select), not free text", async () => {
+  server.use(
+    http.get("http://localhost:8787/models", () =>
+      HttpResponse.json({ models: [{ provider: "zai", id: "glm-5.2" }] }),
+    ),
+  );
+  renderDialog();
+  await userEvent.click(screen.getByRole("button", { name: /nuova/i }));
+
+  // Model dropdown present; no free-text input.
+  const modelSelect = await screen.findByRole("combobox", { name: /modello/i });
+  expect(modelSelect.tagName).toBe("SELECT");
+  expect(screen.queryByTestId("model-freetext")).not.toBeInTheDocument();
+  // Option label combines provider/id.
+  expect(screen.getByRole("option", { name: "zai/glm-5.2" })).toBeInTheDocument();
+});
+
+test("submitting calls createSession with the expected body keys", async () => {
+  let body: unknown = null;
+  server.use(
+    http.get("http://localhost:8787/models", () => HttpResponse.json({ models: [] })),
+    http.post("http://localhost:8787/sessions", async ({ request }) => {
+      body = await request.json();
+      return HttpResponse.json({ id: "s1" });
+    }),
+  );
+  const { onCreated } = renderDialog();
+  await userEvent.click(screen.getByRole("button", { name: /nuova/i }));
+
+  const textarea = await screen.findByLabelText(/domanda/i);
+  await userEvent.type(textarea, "Quante vendite nel 2025?");
+  await userEvent.click(screen.getByRole("button", { name: /^crea$/i }));
+
+  await waitFor(() => {
+    expect(body).toEqual({ workspace: "default", question: "Quante vendite nel 2025?" });
+  });
+  await waitFor(() => expect(onCreated).toHaveBeenCalledWith("s1"));
+});

frontend/src/shell/NewSessionDialog.tsx

@@ -38,8 +38,18 @@ export function NewSessionDialog({ onCreated }: Props) {
     enabled: open,
   });
 
-  const modelList: string[] = Array.isArray(modelsData?.models)
-    ? (modelsData.models as string[])
+  // Model entries may be plain strings or objects ({ id, provider, ... });
+  // normalize to { value, label } so the dropdown renders either shape.
+  const modelList: { value: string; label: string }[] = Array.isArray(
+    modelsData?.models,
+  )
+    ? modelsData.models.map((m) => {
+        if (typeof m === "string") return { value: m, label: m };
+        const o = m as { id?: string; provider?: string };
+        const value = o.id ?? "";
+        const label = o.provider ? `${o.provider}/${value}` : value;
+        return { value, label };
+      })
     : [];
 
   // When workspace list loads, pre-select the first one if nothing chosen yet
@@ -140,8 +150,8 @@ export function NewSessionDialog({ onCreated }: Props) {
               >
                 <option value="">— default —</option>
                 {modelList.map((m) => (
-                  <option key={m} value={m}>
-                    {m}
+                  <option key={m.value} value={m.value}>
+                    {m.label}
                   </option>
                 ))}
               </select>