CVE-2026-48050: Arc: Unauthenticated access to Go debug pprof endpoints leaks runtime state and enables CPU-burn DoS

Arc registers Go’s net/http/pprof handlers at /debug/pprof/* via app.Use(pprof.New()) in internal/api/server.go, and /debug/pprof is added to PublicPrefixes in cmd/arc/main.go. The auth middleware short-circuits before the token check on prefix match, so the endpoints are reachable without any authentication.