Add embedded assets, splash screens, and asset loading support

Features added:
- Embedded main.lua and Lua files support (EMBED_MAIN option)
- Embedded assets support (EMBED_ASSETS option)
- Splash screens with dual logo display (always embedded)
- Asset loading progress tracking API (BeginAssetLoading, UpdateAssetLoading, EndAssetLoading)
- Custom font embedding for splash/loading screens
- --log flag for Windows console control
- --no-logo flag to skip splash screens in development
- Python scripts for embedding (embed_lua.py, embed_assets.py, embed_logo.py, embed_font.py)
- Documentation (EMBEDDING.md, ASSET_LOADING.md, SPLASH_SCREENS.md)

This allows building single-executable releases with all Lua code and assets embedded.

include/core.h

@@ -140,6 +140,9 @@ int lcoreGetDirectoryPath( lua_State* L );
 int lcoreGetPrevDirectoryPath( lua_State* L );
 int lcoreGetWorkingDirectory( lua_State* L );
 int lcoreGetApplicationDirectory( lua_State* L );
+int lcoreBeginAssetLoading( lua_State* L );
+int lcoreUpdateAssetLoading( lua_State* L );
+int lcoreEndAssetLoading( lua_State* L );
 int lcoreMakeDirectory( lua_State* L );
 int lcoreChangeDirectory( lua_State* L );
 int lcoreIsPathFile( lua_State* L );

include/lua_core.h

@@ -50,7 +50,7 @@ void assingGlobalFunction( const char* name, int ( *functionPtr )( lua_State* )
 
 bool luaInit( int argn, const char** argc );
 int luaTraceback( lua_State* L );
-void luaCallMain();
+bool luaCallMain();
 void luaCallInit();
 void luaCallUpdate();
 void luaCallDraw();

include/splash.h

@@ -0,0 +1,6 @@
+#pragma once
+
+void splashInit();
+bool splashUpdate( float delta );
+void splashDraw();
+void splashCleanup();