Replace recursive `final.lib.optionalAttrs` with `prev.lib.optionalAttrs` using the `?` operator to check for meshtastic existence safely. This allows the overlay to work with both stable (25.11) and unstable.
Replace recursive `final.lib.optionalAttrs` with `prev.lib.optionalAttrs` using the `?` operator to check for meshtastic existence safely. This allows the overlay to work with both stable (25.11) and unstable.