feat: Add bin directory output for C++ builds

- Update C++/build.bat to create bin/ directory and output executable there
- Update C++/build.sh to create bin/ directory and output executable there
- Update build_all.bat to check for C++/bin/V2GDecoder.exe
- Update build_all.sh to check for C++/bin/V2GDecoder
- Test successful: C++/bin/V2GDecoder.exe working correctly with sample files

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

C++/build.bat

@@ -1,7 +1,10 @@
 @echo off
 echo Building V2GDecoder...
 
-gcc -o V2GDecoder V2GDecoder.c ^
+rem bin 폴더 생성
+if not exist "bin" mkdir bin
+
+gcc -o bin/V2GDecoder V2GDecoder.c ^
     src/iso1/*.c ^
     src/iso2/*.c ^
     src/din/*.c ^
@@ -12,7 +15,10 @@ gcc -o V2GDecoder V2GDecoder.c ^
     -I./src/din
 
 if %ERRORLEVEL% EQU 0 (
-    echo Build successful! V2GDecoder.exe created.
+    echo Build successful! bin/V2GDecoder.exe created.
+    echo.
+    echo Usage:
+    echo   bin\V2GDecoder.exe ..\Sample\test5.exi
 ) else (
     echo Build failed with error code %ERRORLEVEL%
 )