Summary: AI Gateway is now generally available

Why It Matters: This shows a new product is ready for everyone to use.

What Changed:

• Removed "Log In" and "Contact" links.
• Removed "Sign Up" links.
• Added a new section about "AI Gateway" being generally available.
• Added a link to "Win AI Credits."
• Removed a section about Vercel being named a Visionary in a Gartner report.
• Updated numbers in the "Observability" section.
• Removed a line about nodes on the globe sending pulses.