Add flexible module loading and complete file embedding

- Support any folder structure (no hard-coded folders)
 - Embed all file types recursively from any folder
 - Fix require() dot-to-slash conversion for embedded modules
 - Clean build folder for fresh builds every time
 - Generate empty headers for Lua-only projects

 Backward compatible with existing projects.

scripts/build_release.bat

@@ -24,21 +24,48 @@ if errorlevel 1 (
     exit /b 1
 )
 
+REM ALWAYS clean build folder for fresh build
+echo Cleaning build directory for fresh build...
+del /Q /S * >nul 2>&1
+for /d %%p in (*) do rmdir "%%p" /s /q >nul 2>&1
+echo * Build directory cleaned
+echo.
+
 REM Clean old embedded files
-echo Cleaning old embedded files...
+echo Ready for fresh build...
 del /Q embedded_main.h embedded_assets.h 2>nul
 
-REM Check for Lua files
+REM Auto-copy from game folder if it exists
 echo.
+if exist "..\game" (
+    echo Found game/ folder - auto-copying ALL contents to build...
+    
+    REM Copy all files from game folder recursively, excluding LSP files
+    xcopy /E /I /Y /EXCLUDE:..\game\ReiLua_API.lua+..\game\.luarc.json "..\game\*" . >nul 2>&1
+    if exist "..\game\ReiLua_API.lua" del /Q "ReiLua_API.lua" 2>nul
+    if exist "..\game\.luarc.json" del /Q ".luarc.json" 2>nul
+    
+    echo   * Copied ALL game files and folders
+    echo   * All folder structures preserved ^(user-created folders included^)
+    echo.
+)
+
+REM Check for Lua files
 echo Checking for Lua files...
 dir /b *.lua >nul 2>&1
 if errorlevel 1 (
     echo.
     echo WARNING: No Lua files found in build directory!
     echo.
-    echo Please copy your Lua files:
-    echo   cd build
-    echo   copy ..\your_game\*.lua .
+    if exist "..\game" (
+        echo No Lua files found in game/ folder.
+        echo Add your main.lua to game/ folder and try again.
+    ) else (
+        echo Tip: Create a game/ folder in project root and add main.lua there.
+        echo Or manually copy files:
+        echo   cd build
+        echo   copy ..\your_game\*.lua .
+    )
     echo.
     set /p CONTINUE="Do you want to continue anyway? (y/N): "
     if /i not "%CONTINUE%"=="y" exit /b 1
@@ -47,24 +74,22 @@ if errorlevel 1 (
     dir /b *.lua
 )
 
-REM Check for assets folder
+REM Check for non-Lua data files (any folder, any file type)
 echo.
-echo Checking for assets...
-if not exist "assets" (
-    echo.
-    echo WARNING: No assets folder found!
-    echo.
-    echo To embed assets, create the folder and copy files:
-    echo   cd build
-    echo   mkdir assets
-    echo   copy ..\your_game\assets\* assets\
-    echo.
-    set /p CONTINUE="Do you want to continue without assets? (y/N): "
-    if /i not "%CONTINUE%"=="y" exit /b 1
-    set EMBED_ASSETS=OFF
-) else (
-    echo Found assets folder
+echo Checking for data files to embed...
+set DATA_COUNT=0
+for /r %%f in (*) do (
+    echo %%~nxf | findstr /i /v ".lua .exe .o .a CMake Makefile" >nul
+    if not errorlevel 1 set /a DATA_COUNT+=1
+)
+
+if %DATA_COUNT% GTR 0 (
+    echo Found data files to embed
+    echo   ^(includes: images, sounds, config, data, and any other files^)
     set EMBED_ASSETS=ON
+) else (
+    echo No non-Lua files found ^(only Lua code will be embedded^)
+    set EMBED_ASSETS=OFF
 )
 
 echo.
@@ -72,7 +97,7 @@ echo ================================
 echo Build Configuration
 echo ================================
 echo Lua Embedding:    ON
-echo Asset Embedding:  %EMBED_ASSETS%
+echo Data Embedding:   %EMBED_ASSETS%
 echo Build Type:       Release
 echo ================================
 echo.