Add --version Flag to CLI for Version Display

[Luis-Leao-rbcx]

This pull request introduces a new --version flag to the PromptShell command-line interface, allowing users to easily check the installed version of the package directly from the terminal.

Key Features:

• Users can run promptshell --version to display the current version.
• The output is clean and user-friendly, showing the version in the format: PromptShell v0.1.1.
• This addition enhances user experience by providing quick access to version information.

Acceptance Criteria:

• The --version flag is fully functional and integrated into the CLI.
• The version displayed matches the one defined in pyproject.toml.
• A test has been added to validate this behavior in the tests folder.