- Added findGitCommand() method to check for git in common locations:
* /usr/bin/git (standard Linux)
* /bin/git (alternative location)
* /usr/local/bin/git (compiled from source)
* Falls back to 'which git' and 'command -v git'
- Uses absolute git path in all shell commands
- Fixes 'Git command not found' error on systems where git is not in PATH
- No dependencies added, uses PHP file_exists() + is_executable() checks