Implement base controller for shared functionality; update existing controllers to inherit from BaseController and adjust user ID handling. Add JWT authentication support and modify item retrieval methods in GameDataController.

.gitignore

@@ -6,4 +6,6 @@ appsettings.Development.json
 *.db
 *.db-shm
 *.db-wal
-*.csproj.user
+*.csproj.user
+
+game-data