userServicesFromView returned a nil slice when a node advertised no
services, which (combined with the omitempty tag) caused the
services field to be dropped or serialize as null instead of [].
TypeScript declares services as a non-optional array, so JS callers
calling .find()/.some() on it would throw intermittently depending on
which netmap snapshot they observed.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>