Two bugs reported in #24:
1. `python -m invisible_playwright version` printed the literal "0.1.0"
regardless of the installed version. Root cause: __version__ in
__init__.py was hardcoded and never bumped when the package version
moved past 0.1.0. Fix: read from importlib.metadata so __version__
stays in lockstep with pyproject.toml's `version` field by construction.
2. `python -m invisible_playwright --version` errored with "the
following arguments are required: cmd". Root cause: the parser had
`required=True` on its subparsers and no top-level --version flag.
Fix: add a top-level `--version`/`-V` flag using argparse's standard
version action, drop `required=True`, and reroute the "no subcommand"
case through parser.error() so the existing test_no_subcommand_errors
contract is preserved.
7 new unit tests pin both behaviours so they can't regress silently.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
