Sync OpenAPI spec: add 5 missing endpoints

[mintlify]

Summary

Syncs openapi.json from d-sports-api after d-sports-ecosystem/d-sports-api@e51b976 (feat: update backend to support our move to supabase).

Trigger repo files changed

The commit adds the entire d-sports-api codebase including all app/api/** routes and the initial openapi.json.

What changed in docs

api-reference/openapi.json — added 5 public-facing endpoints that were present in code but missing from the OpenAPI spec:

Endpoint	Method	Description
/api/user/check-username	GET	Check username availability (no auth)
/api/user/all	GET	Paginated list of onboarded users with optional exclude-following filter
/api/thirdweb-link	POST	Create a Thirdweb link for the authenticated user
/api/thirdweb-proxy	GET, POST	Proxy requests to allowed Thirdweb RPC/embedded-wallet endpoints
/api/v1/product_entitlement_mapping	GET	RevenueCat product-to-entitlement mapping

Admin-only routes (/api/leaderboard/reset, /api/rewards/admin-override, /api/pregen-wallet) and test/debug/cron routes were intentionally excluded from the public spec.