Record germination tests on a lot and surface the result.
- GerminationEntry model with a derived rate (germinated / sample). VarietyLot
carries its tests (most-recent first) and exposes latestGerminationRate.
- VarietyRepository.addGerminationTest; watchVariety now also re-emits on
germination-test changes, so the detail refreshes live.
- Detail UI: each lot shows a germination % badge and a grass action that opens
a sheet listing past tests and adding a new one (germinated + sample size).
i18n strings (ES/EN).
Tests: derived-rate + reactivity at the repository, and a widget test for the
record-test → badge flow. Full suite: 35 passing, 0 skipped.