Call this first to turn a place name from the user into an op_id for find_route. Diacritics
are ignored. An empty candidate list is a valid answer (the place was not found), not an error.

Call resolve_operational_point first to get valid op_id values. Call this before
check_train_compatibility or assess_weather_risk: both need the route this returns.

Call find_route first and pass its route as `route`, or pass `section_ids` to check a specific
segment (e.g. after adjusting a route). Exactly one of the two is required.

Call find_route first (for `route` or its section_ids) and the existing OpenWeather MCP
server's `weather` tool for forecasts at find_route's waypoints, before calling this.
Exactly one of `route` or `section_ids` is required, same as check_train_compatibility.

Call find_route first and pass its route as `route`, or pass `section_ids`, same as
check_train_compatibility. Give at least one locomotive via `fleet_ids` (ids from
data/locomotives.yaml) or `custom_locomotives`. A run with no locomotive able to cover
it (unknown/non-electrified energy system, or unmatched signalling) is uncovered, not
an error.