Add solution for "Day 8: Playground", part 1

src/main.rs

@@ -2,7 +2,12 @@ use advent_of_code_2025::solvers;
 
 fn main() {
     println!("### Advent of Code 2025 ###\n");
+    // SecretEntrance
+    // GiftShop
+    // Lobby
     solvers::run(solvers::printing_department::PrintingDepartment {});
     solvers::run(solvers::cafeteria::Cafeteria {});
     solvers::run(solvers::trash_compactor::TrashCompactor {});
+    // Laboratories
+    solvers::run(solvers::playground::Playground::new(None));
 }