- locale-install.test.js: verify locale:uk-ua resolves to docs-uk-ua,
the uk alias dry-run resolves the same plan, and a real (non-dry-run)
--locale uk-UA install lands files under docs/uk-UA
- install-manifests.test.js: assert every SUPPORTED_LOCALES alias
resolves to a real component whose modules exist on disk, guarding
against orphaned locale:<id> entries like the one this PR fixes
Adds de-DE docs, installer wiring, and locale tests. Pre-validated on current main with install manifest checks, markdownlint, locale-install tests, and ECC 2.0 release-surface tests.