Simplify build process: CUDA support now included by default

Since pyproject.toml is configured to use PyTorch CUDA index by default,
all builds automatically include CUDA support. Removed redundant separate
CUDA build scripts and updated documentation.

Changes:
- Removed build-cuda.sh and build-cuda.bat (no longer needed)
- Updated build.sh and build.bat to include CUDA by default
  - Added "uv sync" step to ensure CUDA PyTorch is installed
  - Updated messages to clarify CUDA support is included
- Updated BUILD.md to reflect simplified build process
  - Removed separate CUDA build sections
  - Clarified all builds include CUDA support
  - Updated GPU support section
- Updated CLAUDE.md with simplified build commands

Benefits:
- Simpler build process (one script per platform instead of two)
- Less confusion about which script to use
- All builds work on any system (GPU or CPU)
- Automatic fallback to CPU if no GPU available
- pyproject.toml is single source of truth for dependencies

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

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

build.bat

@@ -1,15 +1,21 @@
 @echo off
-REM Build script for Windows
+REM Build script for Windows with CUDA support (falls back to CPU if no GPU)
 
 echo Building Local Transcription for Windows...
 echo ==========================================
 echo.
+echo This build includes CUDA support and works on both GPU and CPU systems.
+echo.
 
 REM Clean previous builds
 echo Cleaning previous builds...
 if exist build rmdir /s /q build
 if exist dist rmdir /s /q dist
 
+REM Sync dependencies (uses PyTorch CUDA from pyproject.toml)
+echo Installing dependencies with CUDA support...
+uv sync
+
 REM Remove enum34 if present (incompatible with PyInstaller)
 echo Removing enum34 (if present)...
 uv pip uninstall -q enum34 2>nul
@@ -24,6 +30,8 @@ if exist "dist\LocalTranscription" (
     echo Build successful!
     echo Executable location: dist\LocalTranscription\LocalTranscription.exe
     echo.
+    echo CUDA Support: YES (automatically falls back to CPU if no GPU detected^)
+    echo.
     echo To run the application:
     echo   cd dist\LocalTranscription
     echo   LocalTranscription.exe