Codecov flagged the calendar transformProps and the calendar/chord/
country-map plugin index modules as uncovered. Add plugin-registration
tests (instantiate the plugin, assert v1 metadata and the buildQuery
loader), a calendar transformProps test (v1 reshape plus display-option
passthrough, and the non-array passthrough branch), and a calendar
buildQuery case for an unrecognized subdomain granularity falling back to
minutes.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
