feat: Add Cursor setup step to UI setup wizard

- Introduced a new `CursorSetupStep` component for optional Cursor CLI configuration during the setup process.
- Updated `SetupView` to include the cursor step in the setup flow, allowing users to skip or proceed with Cursor CLI setup.
- Enhanced state management to track Cursor CLI installation and authentication status.
- Updated Electron API to support fetching Cursor CLI status.
- Marked completion of the UI setup wizard phase in the integration plan.

apps/ui/src/lib/electron.ts

@@ -551,6 +551,19 @@ export interface ElectronAPI {
       user: string | null;
       error?: string;
     }>;
+    getCursorStatus?: () => Promise<{
+      success: boolean;
+      installed?: boolean;
+      version?: string | null;
+      path?: string | null;
+      auth?: {
+        authenticated: boolean;
+        method: string;
+      };
+      installCommand?: string;
+      loginCommand?: string;
+      error?: string;
+    }>;
     onInstallProgress?: (callback: (progress: any) => void) => () => void;
     onAuthProgress?: (callback: (progress: any) => void) => () => void;
   };