feat: global error fallback and e2e (#91)

* fix(ui): add global route fallback with error toast and retry

* test(e2e): cover cloud accounts error fallback UI

src/tests/e2e/app.spec.ts

@@ -2,13 +2,72 @@ import { test, expect, ElectronApplication } from '@playwright/test';
 import { _electron as electron } from 'playwright';
 import path from 'path';
 
+const injectCloudAccountsFailureScript = `
+(() => {
+  const START_ORPC_SERVER = 'start-orpc-server';
+  const originalPostMessage = window.postMessage.bind(window);
+
+  window.postMessage = function (message, targetOrigin, transfer) {
+    if (message === START_ORPC_SERVER && Array.isArray(transfer) && transfer[0]) {
+      const serverPort = transfer[0];
+      if (typeof serverPort.start === 'function') {
+        serverPort.start();
+      }
+
+      serverPort.onmessage = (event) => {
+        try {
+          const request = typeof event.data === 'string' ? JSON.parse(event.data) : event.data;
+          const requestId = request && (request.i || request.id);
+          const requestUrl = (request && request.p && request.p.u) || '';
+
+          if (!requestId) {
+            return;
+          }
+
+          if (requestUrl.includes('/cloud/listCloudAccounts')) {
+            serverPort.postMessage(
+              JSON.stringify({
+                i: requestId,
+                p: { s: 500, b: { json: { message: 'internal server error' } } },
+              }),
+            );
+            return;
+          }
+
+          let result = null;
+          if (requestUrl.includes('/process/isProcessRunning')) {
+            result = false;
+          } else if (requestUrl.includes('/cloud/getAutoSwitchEnabled')) {
+            result = false;
+          }
+
+          serverPort.postMessage(
+            JSON.stringify({
+              i: requestId,
+              p: { b: { json: result } },
+            }),
+          );
+        } catch (_error) {
+          // Ignore malformed messages in E2E bridge stub.
+        }
+      };
+
+      return;
+    }
+
+    return originalPostMessage(message, targetOrigin, transfer);
+  };
+})();
+`;
+
 test.describe('Antigravity Manager', () => {
   let electronApp: ElectronApplication;
+  const electronMainPath = path.join(__dirname, '../../../.vite/build/main.js');
 
   test.beforeAll(async () => {
     // Launch Electron app
     electronApp = await electron.launch({
-      args: [path.join(__dirname, '../../../.vite/build/main.js')],
+      args: [electronMainPath],
     });
   });
 
@@ -23,8 +82,8 @@ test.describe('Antigravity Manager', () => {
     const title = await window.title();
     expect(title).toBe('Antigravity Manager');
 
-    // Check for main elements - h2 is present (contains i18n content)
-    await expect(window.locator('h2').first()).toBeVisible();
+    await expect(window.getByRole('main')).toBeVisible();
+    await expect(window.locator('a[href="/settings"]').first()).toBeVisible();
   });
 
   test('should navigate to settings', async () => {
@@ -38,6 +97,24 @@ test.describe('Antigravity Manager', () => {
     await expect(window.locator('h2').first()).toBeVisible();
   });
 
+  test('should show fallback UI when cloud accounts loading fails', async () => {
+    await electronApp.close();
+
+    electronApp = await electron.launch({
+      args: [electronMainPath],
+    });
+
+    const page = await electronApp.firstWindow();
+    await page.addInitScript(injectCloudAccountsFailureScript);
+    await page.reload();
+    await page.waitForLoadState('domcontentloaded');
+    const mainContent = page.getByRole('main');
+    await expect(mainContent.getByTestId('cloud-load-error-fallback')).toBeVisible({
+      timeout: 15000,
+    });
+    await expect(mainContent.getByTestId('cloud-load-error-retry')).toBeVisible();
+  });
+
   // More detailed tests would require mocking IPC or having a real environment
   // For now, we verify basic navigation and rendering
 });