Завершить контентную архитектуру этапа 4

level-format/src/main/java/com/projectsacrifice/game/LevelResourceSource.java

@@ -0,0 +1,10 @@
+package com.projectsacrifice.game;
+
+import java.io.IOException;
+import java.io.Reader;
+
+/** Boundary used by Android resources, desktop files, and in-memory tests. */
+@FunctionalInterface
+public interface LevelResourceSource {
+    Reader open(String path) throws IOException;
+}