fix(deps): Separate bundled directory name from executable name

Core Issue:
- ImageMagick v7+ executable is "magick.exe" but directory is "imagemagick"
- Bundled location check was looking in wrong directory

Changes:
- Added bundled_dir_name() - returns MSI installer directory name
- Added exe_name() - returns actual executable name (handles magick.exe)
- Moved bundled location check into Dependency::find_executable()
- Added extensive debug logging for troubleshooting
- Simplified find_tool_path() to avoid duplication

Directory Structure (bundled):
  C:\Program Files\nameback\deps\exiftool\exiftool.exe ✓
  C:\Program Files\nameback\deps\tesseract\tesseract.exe ✓
  C:\Program Files\nameback\deps\ffmpeg\ffmpeg.exe ✓
  C:\Program Files\nameback\deps\imagemagick\magick.exe ✓

Detection Priority:
  1. Bundled MSI location (Windows only)
  2. PATH environment variable
  3. Scoop shims / Chocolatey bin (fallback)

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

Co-Authored-By: Claude <[email protected]>

Release v0.2.3 - Cross-platform binaries with Homebrew support