v3.1.0

Added

• Multiple cities can now coexist in the same scene (SPEC 16). TrafficNetwork and
  PedestrianNetwork build their graph nodes relative to their own root's transform
  (transform.TransformPoint/TransformDirection) instead of in absolute world space, so a
  CityGeneratorRoot copied to a new position (only translation is supported — see the user
  manual) keeps a correct graph. Traffic light/intersection matching is scoped to each network's
  own CityGeneratorRoot hierarchy (falling back to a scene-wide search when there is none), so
  two cities in the same scene never cross-match each other's signals.
• New Tools > City Generator > Rebuild Minimap menu: recaptures the minimap snapshot for the
  city/cities currently in the scene at their current position, without regenerating anything —
  fixes a minimap left out of sync after moving a CityGeneratorRoot by hand. With two or more
  cities, captures one snapshot covering the union of their footprints (with an editable
  resolution) and points every one of their MinimapData at it, merging their Points of Interest.
• MinimapData.localCenter/localSize: each city's own footprint in its root's local space,
  invariant to moving the root — the stable source Rebuild Minimap reads instead of
  recalculating the footprint from scratch or trusting Renderer.bounds.
• MinimapHUD now picks whichever city's captured footprint contains the player (falling back to
  the closest by centre distance) instead of always resolving the first MinimapData found —
  needed once more than one city can have the Minimap enabled at once.
• Rebuild City in Current Scene now handles two or more CityGeneratorRoots in the active scene:
  with one confirmation dialog naming them, it destroys all of them and leaves only the newly
  generated city (unchanged behaviour with zero or one).
• Assets/Tests/EditMode/Generation/MultiCityNetworkTests.cs — synthetic multi-root coverage for
  the coordinate-relativity and hierarchy-scoping rules above.