Bump version to 0.6.0 and add version check command

[melonattacker]

This pull request updates the versioning system of the Prompt Hardener project from hardcoded version strings to a dynamic, centralized approach. It introduces a new __version__ attribute in the package, ensures all components and reports reference this version, and adds a user-friendly CLI version command. The documentation, test fixtures, and tests are also updated to reflect the new versioning scheme.

Versioning and Metadata Improvements

• Introduced a central __version__ = "0.6.0" and PRODUCT_NAME in src/prompt_hardener/__init__.py, along with a get_version_display() helper. All internal references to the tool version now import this value instead of using hardcoded strings. [1] [2] [3] [4] [5] [6]
• Updated pyproject.toml to use dynamic versioning, pulling the version from the package attribute instead of a static value. [1] [2]

CLI Enhancements

• Added a version subcommand and -v/--version flags to the CLI, displaying the tool version using the new dynamic system. Updated the argument parsing to support these features and improved test coverage for them. [1] [2] [3] [4] [5] [6]

Documentation and Example Updates

• Updated all installation instructions and tutorial outputs in README.md and docs/tutorials.md to reference version 0.6.0 instead of 0.5.0. [1] [2] [3] [4]

Test and Fixture Synchronization

• Updated test fixtures and test assertions to expect the dynamic version value, ensuring consistency across the codebase. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16]

These changes make the versioning process more robust, reduce manual update errors, and improve the user and developer experience.