Uses the real parse_args() function to get CLI defaults, so when
new arguments are added they're automatically available to all tests.
Changes:
- Add tests/conftest.py with create_args fixture
- Update 8 test files to use shared fixture
- Remove duplicate _create_mock_args methods
- Remove redundant @pytest.fixture mock_args definitions
This eliminates the need to update multiple test files when
adding new CLI arguments.
Refactors error handling to retry all 5xx errors (not just 502), network errors (URLError, socket.error, IncompleteRead), and JSON parse errors with exponential backoff and jitter. Respects retry-after and rate limit headers per GitHub API requirements. Consolidates retry logic into make_request_with_retry() wrapper and adds clear logging for retry attempts and failures. Removes dead code from 2016 (errors list, _request_http_error, _request_url_error) that was intentionally disabled in commit 1e5a9048 to fix#29.
Fixes#140, #110, #138