Add real-time MEV refund metrics to navbar

[odysseus0]

Summary

• Add MEV refund metrics widget component that displays real-time data from Dune Analytics
• Integrate widget into the navbar to show MEV and gas refund values
• Replace hardcoded mock values with live data from the production API

Changes

1. New MEV metrics widget component (src/components/MevMetrics.tsx)

   • Fetches data from https://refund-metrics-dune-api.vercel.app/api/metrics
   • Shows loading state while fetching
   • Falls back to mock data on errors
   • Displays values formatted as "X.XX ETH"

2. Navbar integration

   • Added custom navbar item type support
   • Configured widget to appear in navbar between docs/API links and GitHub link

Testing

• Tested locally with yarn start
• Widget successfully displays live data: MEV Refund: 403.64 ETH, Gas Refund: 751.80 ETH
• Error handling verified by blocking API requests
• No CORS issues when fetching from the API

Screenshots

Widget displaying in navbar:

Flashbots | Docs | API | Refund | MEV: 403.64 ETH | Gas: 751.80 ETH | GitHub 

🤖 Generated with Claude Code

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Project	Deployment	Preview	Comments	Updated (UTC)
flashbots-docs	Ready	Preview	Comment	Aug 26, 2025 10:50am

[odysseus0]

Update: Added feature flag support

I've pushed an update that adds runtime feature flag support to control widget visibility:

Changes in this update:

• Widget now checks showWidget field from API response
• Returns null early when showWidget === false to completely hide the widget
• Maintains backward compatibility - displays widget if field is missing
• Clean implementation with no flash of content during loading

Testing completed:

• ✅ Widget displays normally when showWidget: true
• ✅ Widget is completely hidden when showWidget: false
• ✅ Toggle works at runtime via API environment variable

This allows us to control widget visibility across all sites from a single point (the API's environment variable) without requiring frontend redeployments.

[odysseus0]

Ready for review - navbar alignment fixed with consistent typography hierarchy