Clean up old Vercel project and legacy Cloudflare Worker

[MarketDataApp]

Context

The docs site has been migrated from Vercel to Cloudflare Pages (completed 2026-02-24). The old infrastructure is still in place but no longer serving traffic.

Tasks

• Delete the old Cloudflare Worker that was routing /docs/* and /docs-staging/* to Vercel
• Delete the Vercel project (both staging and production)
• Optionally remove docs.marketdata.app and docs-staging.marketdata.app DNS records if no longer needed
• Delete the dev branch (replaced by staging)

Notes

• Vercel git integration has already been disconnected
• Old Worker routes have already been removed; only the Worker itself remains
• Allow a week of monitoring before cleanup to confirm everything is stable
• Rollback if needed: reconnect Vercel git integration, re-add old Worker routes