Add build system for native applications

- PyInstaller spec file for cross-platform builds
- Build scripts for Linux/macOS (build.sh) and Windows (build.bat)
- requirements.txt with all dependencies
- Updated README with build and installation instructions
- Support for creating standalone executables for all platforms

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

build.bat

@@ -0,0 +1,44 @@
+@echo off
+REM Build script for Word Search application (Windows)
+
+echo =========================================
+echo Word Search Application Builder
+echo =========================================
+echo.
+
+REM Check if PyInstaller is installed
+pyinstaller --version >nul 2>&1
+if %errorlevel% neq 0 (
+    echo PyInstaller not found. Installing dependencies...
+    pip install -r requirements.txt
+)
+
+REM Clean previous builds
+echo Cleaning previous builds...
+if exist build rmdir /s /q build
+if exist dist rmdir /s /q dist
+
+echo Building for platform: Windows
+echo.
+
+REM Build the application
+echo Running PyInstaller...
+pyinstaller word_search.spec
+
+REM Check if build was successful
+if exist dist (
+    echo.
+    echo =========================================
+    echo Build completed successfully!
+    echo =========================================
+    echo.
+    echo Platform: Windows
+    echo Output location: dist\
+    echo Executable: dist\WordSearch.exe
+    echo.
+    echo To run: dist\WordSearch.exe
+) else (
+    echo.
+    echo Build failed! Check the error messages above.
+    exit /b 1
+)