Adds a streamlined 4-step onboarding flow for non-technical users:
- Welcome page with feature overview
- One-click OAuth sign-in with auto-clipboard detection
- Simplified permissions page (core permissions only)
- Auto-setup of gateway, CLI, and workspace
The Easy Setup is now shown by default on first launch. Power users
can click "Advanced Setup" to access the full onboarding wizard with
gateway mode selection, remote configuration, etc.
This makes the DMG install experience much simpler for laymen who
just want to download and go.
