Fix package structure and lazy-import ODT formatter

Add missing __init__.py to formatters/ so setuptools.find_packages
includes the subpackage in wheel/sdist builds (#16).

Move ODTFormatter import from top-level to lazy import inside
get_formatter_by_extension() so missing odfpy no longer crashes module
load before main() runs. Remove dead except ImportError handler in
cli.py save() block; surface a clear 'odfpy is not installed' message
when the formatter factory returns None for .odt (#25).

Closes #16, closes #25

tests/test_cli.py

@@ -94,3 +94,17 @@ def test_cli_output_without_extension(mock_fetch, tmp_path):
     output = str(tmp_path / "report")
     code = main(["--date", "2026-01-01--2026-01-31", "--output", output])
     assert code == 1
+
+
+@mock.patch.dict(os.environ, VALID_ENV, clear=True)
+@mock.patch("redmine_reporter.cli.fetch_issues_with_spent_time")
+@mock.patch("redmine_reporter.cli.get_formatter_by_extension")
+def test_cli_odt_missing_odfpy_message(mock_gf, mock_fetch, tmp_path, capsys):
+    """При запросе .odt без odfpy — выход 1, понятное сообщение про odfpy."""
+    mock_fetch.return_value = []
+    mock_gf.return_value = None
+    output = str(tmp_path / "report.odt")
+    code = main(["--date", "2026-01-01--2026-01-31", "--output", output])
+    assert code == 1
+    captured = capsys.readouterr()
+    assert "odfpy" in captured.err