feat(simulator): ✨ Add collectibles inventory, state tracking, and interaction endpoints to the city simulation API

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

src/simulator/api-gdext/src/lib.rs

@@ -1295,6 +1295,7 @@ impl GdCity {
                 gold: d.gold,
                 culture: d.culture,
                 science: d.science,
+                collectibles: vec![],
             })
             .collect()
     }