Remove SDK cards from API reference overview page

[kylemclaren]

Summary

• Removes the SDK Libraries section from the generated API reference index page
• SDK pages don't all exist yet, so removing the links until they're ready

Test plan

• Build passes

🤖 Generated with Claude Code

[github-actions]

CLI Documentation Generator

Metric	Value
CLI Version	0.0.1
Commands Generated	24
Tests	✅ 0/0 passed

📚 Commands documented

• sprite login
• sprite logout
• sprite org auth
• sprite org list
• sprite org logout
• sprite org keyring disable
• sprite org keyring enable
• sprite auth setup
• sprite create
• sprite use
• sprite list
• sprite destroy
• sprite exec
• sprite console
• sprite checkpoint create
• sprite checkpoint list
• sprite checkpoint info
• sprite checkpoint delete
• sprite restore
• sprite proxy
• sprite url
• sprite url update
• sprite api
• sprite upgrade

[github-actions]

Preview Deployment

Name	URL
Preview	https://pr-101-superfly-sprites-docs.fly.dev

Commit: dc0ed82

[github-actions]

Lighthouse Results

URL	Performance	Accessibility	Best Practices	SEO
/	🟠 86	🟢 100	🟢 96	🟢 100

[github-actions]

E2E Test Results

✅ Tests success

Ran against: https://pr-101-superfly-sprites-docs.fly.dev