v0.2.1: Auto-fetch route metadata on cold cache

Auto-fetch route metadata on cold cache

When eia_query_route is called without a prior eia_describe_route, the service
now fetches and caches route metadata on-demand before querying, eliminating
silent data-empty results on cold start.

Fixed:

• eia_query_route auto-describes the route when the metadata cache is cold (#17)

59 tests pass; bun run devcheck clean.