Get Cities Directory

Public endpoint: State→City cascading-selector directory.

Returns live cities (is_active AND NOT coming_soon) grouped by normalized state, sorted by state display name then city name, plus the distinct state codes of coming-soon cities (a code may appear in BOTH lists when a state has live and coming-soon cities — the frontend's tier logic handles the overlap). Building counts come from ONE aggregate query (Building has no is_active/archived flag, so all rows count). Cities whose state string fails normalization are excluded rather than crashing the response.