test: migrate to MSW testing architecture for App integration test

Major testing infrastructure upgrade from manual mocks to Mock Service Worker (MSW):

New MSW infrastructure (tests/msw/):
- Add state.ts: In-memory state manager with full CRUD operations
  - Manage providers and current selections per app type (Claude/Codex)
  - Auto-switch current provider when deleted
  - Deep clone to prevent reference pollution
- Add handlers.ts: HTTP request handlers for 10 Tauri API endpoints
  - Mock get_providers, switch_provider, add/update/delete_provider
  - Mock update_sort_order, update_tray_menu, import_default_config
  - Support error scenarios (404 for non-existent providers)
- Add tauriMocks.ts: Tauri API mock layer
  - Transparently convert invoke() calls to HTTP requests
  - Mock event listener system with emitTauriEvent helper
  - Use cross-fetch for Node.js environment
- Add server.ts: MSW server setup for Node.js test environment

Refactor App.test.tsx (-170 lines, -43%):
- Remove 23 manual mocks (useProvidersQuery, useProviderActions, etc.)
- Run real hooks with MSW-backed API calls instead of mock implementations
- Test real state changes instead of mock call counts
- Add comprehensive flow: duplicate → create → edit → delete → event listening
- Verify actual provider list changes and current selection updates

Setup integration:
- Add MSW server lifecycle to tests/setupTests.ts
  - Start server before all tests
  - Reset handlers and state after each test
  - Close server after all tests complete
- Clear all mocks in afterEach for test isolation

Dependencies:
- Add msw@^2.11.6 for API mocking
- Add cross-fetch@^4.1.0 for fetch polyfill in Node.js

Type fixes:
- Add missing imports (AppType, Provider) in handlers.ts
- Fix HttpResponse.json generic constraint with as any (MSW best practice)
- Change invalid category "default" to "official" in state.ts

Test results: All 50 tests passing across 8 files, 0 TypeScript errors

tests/msw/handlers.ts

@@ -0,0 +1,100 @@
+import { http, HttpResponse } from "msw";
+import type { AppType } from "@/lib/api/types";
+import type { Provider } from "@/types";
+import {
+  addProvider,
+  deleteProvider,
+  getCurrentProviderId,
+  getProviders,
+  listProviders,
+  resetProviderState,
+  setCurrentProviderId,
+  updateProvider,
+  updateSortOrder,
+} from "./state";
+
+const TAURI_ENDPOINT = "http://tauri.local";
+
+const withJson = async <T>(request: Request): Promise<T> => {
+  try {
+    const body = await request.text();
+    if (!body) return {} as T;
+    return JSON.parse(body) as T;
+  } catch {
+    return {} as T;
+  }
+};
+
+const success = <T>(payload: T) => HttpResponse.json(payload as any);
+
+export const handlers = [
+  http.post(`${TAURI_ENDPOINT}/get_providers`, async ({ request }) => {
+    const { app_type } = await withJson<{ app_type: AppType }>(request);
+    return success(getProviders(app_type));
+  }),
+
+  http.post(`${TAURI_ENDPOINT}/get_current_provider`, async ({ request }) => {
+    const { app_type } = await withJson<{ app_type: AppType }>(request);
+    return success(getCurrentProviderId(app_type));
+  }),
+
+  http.post(`${TAURI_ENDPOINT}/update_providers_sort_order`, async ({ request }) => {
+    const { updates = [], app_type } = await withJson<{
+      updates: { id: string; sortIndex: number }[];
+      app_type: AppType;
+    }>(request);
+    updateSortOrder(app_type, updates);
+    return success(true);
+  }),
+
+  http.post(`${TAURI_ENDPOINT}/update_tray_menu`, () => success(true)),
+
+  http.post(`${TAURI_ENDPOINT}/switch_provider`, async ({ request }) => {
+    const { id, app_type } = await withJson<{ id: string; app_type: AppType }>(
+      request,
+    );
+    const providers = listProviders(app_type);
+    if (!providers[id]) {
+      return HttpResponse.json(false, { status: 404 });
+    }
+    setCurrentProviderId(app_type, id);
+    return success(true);
+  }),
+
+  http.post(`${TAURI_ENDPOINT}/add_provider`, async ({ request }) => {
+    const { provider, app_type } = await withJson<{
+      provider: Provider & { id?: string };
+      app_type: AppType;
+    }>(request);
+
+    const newId = provider.id ?? `mock-${Date.now()}`;
+    addProvider(app_type, { ...provider, id: newId });
+    return success(true);
+  }),
+
+  http.post(`${TAURI_ENDPOINT}/update_provider`, async ({ request }) => {
+    const { provider, app_type } = await withJson<{
+      provider: Provider;
+      app_type: AppType;
+    }>(request);
+    updateProvider(app_type, provider);
+    return success(true);
+  }),
+
+  http.post(`${TAURI_ENDPOINT}/delete_provider`, async ({ request }) => {
+    const { id, app_type } = await withJson<{ id: string; app_type: AppType }>(
+      request,
+    );
+    deleteProvider(app_type, id);
+    return success(true);
+  }),
+
+  http.post(`${TAURI_ENDPOINT}/import_default_config`, async () => {
+    resetProviderState();
+    return success(true);
+  }),
+
+  http.post(`${TAURI_ENDPOINT}/open_external`, () => success(true)),
+
+  http.post(`${TAURI_ENDPOINT}/restart_app`, () => success(true)),
+];

tests/msw/server.ts

@@ -0,0 +1,5 @@
+import { setupServer } from "msw/node";
+import { handlers } from "./handlers";
+
+export const server = setupServer(...handlers);
+

tests/msw/state.ts

@@ -0,0 +1,116 @@
+import type { AppType } from "@/lib/api/types";
+import type { Provider } from "@/types";
+
+type ProvidersByApp = Record<AppType, Record<string, Provider>>;
+type CurrentProviderState = Record<AppType, string>;
+
+const createDefaultProviders = (): ProvidersByApp => ({
+  claude: {
+    "claude-1": {
+      id: "claude-1",
+      name: "Claude Default",
+      settingsConfig: {},
+      category: "official",
+      sortIndex: 0,
+      createdAt: Date.now(),
+    },
+    "claude-2": {
+      id: "claude-2",
+      name: "Claude Custom",
+      settingsConfig: {},
+      category: "custom",
+      sortIndex: 1,
+      createdAt: Date.now() + 1,
+    },
+  },
+  codex: {
+    "codex-1": {
+      id: "codex-1",
+      name: "Codex Default",
+      settingsConfig: {},
+      category: "official",
+      sortIndex: 0,
+      createdAt: Date.now(),
+    },
+    "codex-2": {
+      id: "codex-2",
+      name: "Codex Secondary",
+      settingsConfig: {},
+      category: "custom",
+      sortIndex: 1,
+      createdAt: Date.now() + 1,
+    },
+  },
+});
+
+const createDefaultCurrent = (): CurrentProviderState => ({
+  claude: "claude-1",
+  codex: "codex-1",
+});
+
+let providers = createDefaultProviders();
+let current = createDefaultCurrent();
+
+const cloneProviders = (value: ProvidersByApp) =>
+  JSON.parse(JSON.stringify(value)) as ProvidersByApp;
+
+export const resetProviderState = () => {
+  providers = createDefaultProviders();
+  current = createDefaultCurrent();
+};
+
+export const getProviders = (appType: AppType) =>
+  cloneProviders(providers)[appType] ?? {};
+
+export const getCurrentProviderId = (appType: AppType) => current[appType] ?? "";
+
+export const setCurrentProviderId = (appType: AppType, providerId: string) => {
+  current[appType] = providerId;
+};
+
+export const updateProviders = (appType: AppType, data: Record<string, Provider>) => {
+  providers[appType] = cloneProviders({ [appType]: data } as ProvidersByApp)[appType];
+};
+
+export const setProviders = (appType: AppType, data: Record<string, Provider>) => {
+  providers[appType] = JSON.parse(JSON.stringify(data)) as Record<string, Provider>;
+};
+
+export const addProvider = (appType: AppType, provider: Provider) => {
+  providers[appType] = providers[appType] ?? {};
+  providers[appType][provider.id] = provider;
+};
+
+export const updateProvider = (appType: AppType, provider: Provider) => {
+  if (!providers[appType]) return;
+  providers[appType][provider.id] = {
+    ...providers[appType][provider.id],
+    ...provider,
+  };
+};
+
+export const deleteProvider = (appType: AppType, providerId: string) => {
+  if (!providers[appType]) return;
+  delete providers[appType][providerId];
+  if (current[appType] === providerId) {
+    const fallback = Object.keys(providers[appType])[0] ?? "";
+    current[appType] = fallback;
+  }
+};
+
+export const updateSortOrder = (
+  appType: AppType,
+  updates: { id: string; sortIndex: number }[],
+) => {
+  if (!providers[appType]) return;
+  updates.forEach(({ id, sortIndex }) => {
+    const provider = providers[appType][id];
+    if (provider) {
+      providers[appType][id] = { ...provider, sortIndex };
+    }
+  });
+};
+
+export const listProviders = (appType: AppType) =>
+  JSON.parse(JSON.stringify(providers[appType] ?? {})) as Record<string, Provider>;
+

tests/msw/tauriMocks.ts

@@ -0,0 +1,61 @@
+import "cross-fetch/polyfill";
+import { vi } from "vitest";
+import { server } from "./server";
+
+const TAURI_ENDPOINT = "http://tauri.local";
+
+vi.mock("@tauri-apps/api/core", () => ({
+  invoke: async (command: string, payload: Record<string, unknown> = {}) => {
+    const response = await fetch(`${TAURI_ENDPOINT}/${command}`, {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify(payload ?? {}),
+    });
+
+    if (!response.ok) {
+      const text = await response.text();
+      throw new Error(text || `Invoke failed for ${command}`);
+    }
+
+    const text = await response.text();
+    if (!text) return undefined;
+    try {
+      return JSON.parse(text);
+    } catch {
+      return text;
+    }
+  },
+}));
+
+const listeners = new Map<
+  string,
+  Set<(event: { payload: unknown }) => void>
+>();
+
+const ensureListenerSet = (event: string) => {
+  if (!listeners.has(event)) {
+    listeners.set(event, new Set());
+  }
+  return listeners.get(event)!;
+};
+
+export const emitTauriEvent = (event: string, payload: unknown) => {
+  const handlers = listeners.get(event);
+  handlers?.forEach((handler) => handler({ payload }));
+};
+
+vi.mock("@tauri-apps/api/event", () => ({
+  listen: async (event: string, handler: (event: { payload: unknown }) => void) => {
+    const set = ensureListenerSet(event);
+    set.add(handler);
+    return () => {
+      set.delete(handler);
+    };
+  },
+}));
+
+// Ensure the MSW server is referenced so tree shaking doesn't remove imports
+void server;
+