Add test suite and CI workflow

[Copilot]

Implements test infrastructure for the CLI dispatcher module with GitHub Actions integration.

Changes

• Test suite (tests/test_main.py): 7 test cases covering CLI argument parsing, command validation, and module dispatch logic. Achieves 95% coverage of rhasspy/__main__.py.

• CI workflow (.github/workflows/tests.yml): Runs tests across Python 3.7-3.11 with coverage reporting and Codecov integration. Includes explicit permissions: contents: read to limit GITHUB_TOKEN scope.

• Build artifacts: Updated .gitignore to exclude pytest/coverage artifacts (.coverage, .pytest_cache, htmlcov/, coverage.xml).

Example

def test_main_unknown_command(capsys):
    """Test main() with unknown command shows error."""
    with mock.patch.object(sys, "argv", ["rhasspy", "unknown-command"]):
        with pytest.raises(SystemExit) as exc_info:
            main()
        assert exc_info.value.code == 1

Original prompt

add tests

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