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

Summary Arc registers Go's net/http/pprof handlers at /debug/pprof/ via app.Usepprof.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...