`validate_file_path` now expands leading `~` to the user's home directory before checking file existence, so paths like `~/.ssh/id_rsa` work on macOS and Linux. Also fixes error messages that incorrectly said "Database file".
`validate_file_path` now expands leading `~` to the user's home directory before checking file existence, so paths like `~/.ssh/id_rsa` work on macOS and Linux. Also fixes error messages that incorrectly said "Database file".