Add exe packaging and install.bat

- esbuild bundle + @yao-pkg/pkg for standalone Windows exe
- install.bat copies to %LOCALAPPDATA%\kisync and adds to user PATH
- npm run package to build release/kisync.exe

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

install.bat

@@ -0,0 +1,55 @@
+@echo off
+setlocal
+
+set "INSTALL_DIR=%LOCALAPPDATA%\kisync"
+set "EXE_NAME=kisync.exe"
+
+echo.
+echo  KIS API Builder Sync - Installer
+echo  =================================
+echo.
+
+:: Create install directory
+if not exist "%INSTALL_DIR%" (
+    mkdir "%INSTALL_DIR%"
+    echo  Created: %INSTALL_DIR%
+)
+
+:: Copy exe
+copy /Y "%~dp0release\%EXE_NAME%" "%INSTALL_DIR%\%EXE_NAME%" >nul 2>&1
+if errorlevel 1 (
+    echo  ERROR: Could not copy %EXE_NAME%. Make sure release\kisync.exe exists.
+    echo  Run "npm run package" first to build the exe.
+    pause
+    exit /b 1
+)
+echo  Installed: %INSTALL_DIR%\%EXE_NAME%
+
+:: Check if already in PATH
+echo %PATH% | findstr /I /C:"%INSTALL_DIR%" >nul 2>&1
+if %errorlevel%==0 (
+    echo  PATH: already configured
+    goto :done
+)
+
+:: Add to user PATH
+echo  Adding to user PATH...
+for /f "tokens=2*" %%a in ('reg query "HKCU\Environment" /v Path 2^>nul') do set "USER_PATH=%%b"
+
+if defined USER_PATH (
+    reg add "HKCU\Environment" /v Path /t REG_EXPAND_SZ /d "%USER_PATH%;%INSTALL_DIR%" /f >nul 2>&1
+) else (
+    reg add "HKCU\Environment" /v Path /t REG_EXPAND_SZ /d "%INSTALL_DIR%" /f >nul 2>&1
+)
+
+:: Broadcast environment change so new terminals pick it up
+rundll32.exe user32.dll,UpdatePerIDesktopLayout >nul 2>&1
+
+echo  PATH: added %INSTALL_DIR%
+
+:done
+echo.
+echo  Done! Open a NEW terminal and run:
+echo    kisync --help
+echo.
+pause