feat: Refine Collaborations section, navbar, and remove outdated CTAs

What does this MR do and why?

This MR refines the website's layout stability and streamlines the Collaborations and Summer of AI pages for a more minimalist, professional aesthetic. It improves visual consistency by removing UI clutter (like bulky outline boxes and excessive padding), fixes unintended horizontal layout scrolling, and cleans up outdated promotional sections. It also aligns the test suite with the newly updated design and fixes lingering ESLint warnings.

🚀 Key Features

• Layout Stability: Enforced strict viewport constraints to completely eliminate the cursor-based horizontal swaying bug across the website.
• Structure Page Refinement: Redesigned the "Our Collaborations" section at the bottom of the page to be a highly elegant, compact, and centered glassmorphic card.
• Collaborations Page Cleanup: Removed heavy "outline boxes" from both the 'Partner Type' tags and the 'Focus Area' items, replacing them with a much cleaner, bulleted plain-text design.
• Navbar Simplification: Removed the "Collaborations" link and mega-menu card from the "About" dropdown to streamline navigation.
• Summer of AI Updates: Removed the outdated "Apply for Summer of AI 2024" Call-to-Action section and the "Applications Closed" subtitle.
• Code Health: Resolved any type ESLint warnings in Contact.tsx.
• Pipeline Resolution: Updated tests in Structure.test.tsx, Collaborations.test.tsx, and SummerOfAI.test.tsx to match the new UI, ensuring a 100% passing test pipeline.

❓ Why this change?

• Achieves a "simple and beautiful" design by reducing unnecessary visual weight and redundant spacing.
• Fixes highly distracting layout bugs (horizontal scrolling/swaying) for a premium user feel.
• Removes outdated information (old CTAs, tag clutter) that detracted from the core content.
• Ensures the codebase remains clean, lint-free, and supported by reliable tests.

✅ Checklist

• Layout stability verified (no horizontal sway)
• UI clutter removed (boxes, heavy tags, outdated CTAs)
• Navigation simplified
• Tests updated and passing locally
• Linting passing (ESLint warnings resolved)
• Build successful
• Responsive behavior and Light/Dark themes preserved

Related Issue

#77 (closed)

Screenshots

Before

After

---