Update Career Opportunities image to match theme colors

- Replace career image with black-and-purple-abstract.png
- Perfect match for site's purple/dark theme
- Maintains professional appearance while being visually consistent
- Improves overall visual cohesion of Work With Us section

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

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

Author: Zeff01

apps/codebility/app/(marketing)/_components/landing/LandingWorkWithUs.tsx

@@ -51,7 +51,7 @@ const WORK_WITH_US_CARDS = [
     id: "careers",
     title: "Career Opportunities",
     image: {
-      src: "/assets/images/index/man-sitting.jpg",
+      src: "/assets/images/services/black-and-purple-abstract.png",
       alt: "career opportunities and job openings04",
     },
     description: