[pollychen-lab]

Summary

• add a root-level creator-toolkit --version option
• read the displayed version from installed package metadata
• document the command in the README usage examples
• add unit coverage and installed-entry-point smoke coverage

Linked issue

Closes #15

Why this change

Users and bug reporters can now identify the installed Creator Toolkit CLI package version directly from the command line without relying on package-manager-specific commands.

Compatibility and safety

Existing subcommands, JSON output, manifests, and filesystem behavior are unchanged. The new option exits before subcommand dispatch and prints creator-toolkit-cli <version> from package metadata.

Validation

.venv/bin/ruff check .
.venv/bin/ruff format --check .
.venv/bin/pytest
.venv/bin/python -m build
.venv/bin/python -m twine check dist/*
git diff --check

Checklist

• This PR is focused on one issue and contains no unrelated changes.
• I added or updated tests for behavior changes, or explained why tests are not needed.
• I updated user or contributor documentation when needed.
• I considered backward compatibility and filesystem safety where applicable.
• I ran the relevant local checks and included the results above.
• I did not include secrets, local environments, build output, or real user files.