Function route_paths 

pub fn route_paths(
    pool: &DescriptorPool,
    aliases: &[AliasConfig],
) -> Vec<(String, String)>

The axum paths routes would register for this pool and aliases.

Mirrors the registration in routes (unary RPCs, their config aliases, and server-streaming RPCs) without building handlers, so callers can detect route collisions before mounting additional routes (e.g. a forward-auth endpoint).

Each entry is (method, path) where method is the uppercase HTTP token, so callers can distinguish same-path/different-method routes from real conflicts.