Improve error handling in home directory resolution

[corylanou]

This PR improves error handling when resolving paths that contain the tilde (~) character for home directory expansion. Previously, the homeDirectory() function would log and exit the program if it failed to get the user's home directory. Now it properly returns the error to the caller, allowing for more graceful error handling.

Key changes:

• Modified homeDirectory() to return an error instead of calling log.Fatal()
• Updated the calling code in Execute() to handle potential errors
• Removed unused log import

These changes follow the Go best practice of propagating errors up the call stack rather than terminating the program at the point of failure, giving the caller more control over error handling.