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.

tests/Feature/SignLabelsTest.php

@@ -34,6 +34,8 @@ class SignLabelsTest extends TestCase
         'city.sign_hospital',
         'city.sign_school',
         'city.sign_cityhall',
+        'city.sign_university',
+        'city.sign_firestation',
     ];
 
     /**
@@ -69,7 +71,7 @@ class SignLabelsTest extends TestCase
 
         $html = $this->get('/city')->assertOk()->getContent();
 
-        foreach (['signPlaza', 'signBeach', 'signFood', 'signHospital', 'signSchool', 'signCityhall'] as $jsKey) {
+        foreach (['signPlaza', 'signBeach', 'signFood', 'signHospital', 'signSchool', 'signCityhall', 'signUniversity', 'signFirestation'] as $jsKey) {
             $this->assertStringContainsString($jsKey.':', $html, "Missing i18n entry {$jsKey}");
         }
     }