Add missing 'About Us' section to onboarding stepper

- Add 'About Us' section with id 'about-section' to stepper navigation
- Position it between 'Software Development' and 'What to Expect'
- Ensures all onboarding sections are trackable in the navigation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: yyyort

apps/codebility/app/auth/onboarding/OnboardingStepper.tsx

@@ -7,6 +7,7 @@ import { Check } from "lucide-react";
 // Section configuration - maps to each wrapper component
 const SECTIONS = [
   { id: "software", label: "Software Development" },
+  { id: "about-section", label: "About Us" },
   { id: "expect", label: "What to Expect" },
   { id: "roadmap", label: "Your Roadmap" },
   { id: "house-rules", label: "House Rules" },