staging some future refactoring, .h -> hpp, fix for rendering w/ audio

src/util/file_.hpp

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <filesystem>
+
+namespace anm2ed::util
+{
+  class File
+  {
+  public:
+    File() = default;
+    File(const std::filesystem::path&, const char* mode);
+    ~File();
+
+    bool open(const std::filesystem::path&, const char* mode);
+    int close();
+    FILE* get() const;
+    explicit operator bool() const;
+
+  private:
+    FILE* handle{};
+  };
+}