Adds main process bridge for GitHub Device Flow auth

Enables GitHub Device Flow authentication through the main process
to bypass CORS issues by introducing IPC bridge handlers and updating
the adapter to use them when available. Improves error handling and
logging for easier debugging. Wraps settings in a toast provider to
support user notifications.

index.tsx

@@ -2,6 +2,7 @@ import { init as initGhostty } from 'ghostty-web';
 import ReactDOM from 'react-dom/client';
 import App from './App';
 import SettingsPage from './components/SettingsPage';
+import { ToastProvider } from './components/ui/toast';
 
 // Pre-load Ghostty WASM immediately on app start for faster terminal open
 initGhostty().catch((err) => {
@@ -27,7 +28,11 @@ const root = ReactDOM.createRoot(rootElement);
 const renderApp = () => {
   const route = getRoute();
   if (route === 'settings') {
-    root.render(<SettingsPage />);
+    root.render(
+      <ToastProvider>
+        <SettingsPage />
+      </ToastProvider>
+    );
   } else {
     root.render(<App />);
   }
@@ -37,4 +42,4 @@ const renderApp = () => {
 renderApp();
 
 // Listen for hash changes
-window.addEventListener('hashchange', renderApp);
+window.addEventListener('hashchange', renderApp);