feat(city): add city landmarks, stores, luminous signs, and ATC echo guard

Add university and fire station civic buildings plus 7 new store types,
each with facade and luminous blade signs. Extend landmark material
colors and sign accents. Fix ATC dispatch to reject prompt-echoing AI
responses via heuristic guard. Add CityPlacesTest for collision and
roadway avoidance, and extend AirportTest and SignLabelsTest.

database/seeders/CityContentSeeder.php

@@ -119,7 +119,7 @@ class CityContentSeeder extends Seeder
                 'description' => 'Material de construção e ferramentas.',
                 'type' => 'hardware',
                 'owner_id' => $shopkeeper?->id,
-                'pos_x' => 8, 'pos_y' => 0, 'pos_z' => 6,
+                'pos_x' => 11, 'pos_y' => 0, 'pos_z' => 10,
                 'width' => 10, 'height' => 7, 'depth' => 10,
                 'is_open' => true,
             ],