[nostalgia] Collapse NostalgiaCore down to a single library and cleanup impl data access

src/nostalgia/core/core.hpp

@@ -9,27 +9,22 @@
 #include "assetmanager.hpp"
 #include "clipboard.hpp"
 #include "consts.hpp"
+#include "event.hpp"
 #include "gfx.hpp"
 #include "input.hpp"
 #include "media.hpp"
 
 namespace nostalgia::core {
 
-using event_handler = int(*)(Context*);
-
 ox::Result<ox::UniquePtr<Context>> init(ox::UniquePtr<ox::FileSystem> fs, const char *appName = "Nostalgia") noexcept;
 
 ox::Error run(Context *ctx) noexcept;
 
-// Sets event handler that sleeps for the time given in the return value. The
-// sleep time is a minimum of ~16 milliseconds.
-void setEventHandler(Context *ctx, event_handler) noexcept;
-
 // Returns the number of milliseconds that have passed since the start of the
-//  program.
+// program.
 [[nodiscard]]
 uint64_t ticksMs(Context *ctx) noexcept;
 
-void shutdown(Context *ctx) noexcept;
+ox::Error shutdown(Context *ctx) noexcept;
 
 }