Extend the default corpus doc-nav section and relabel the release log

Kalamar now ships a "corpus" section as the first entry of the doc
navigation; replace it in place (same id) to add the release-log
sub-item. The corpus, composition, useful-subcorpora and named-VC
labels come from the Kalamar defaults now; only the release-log labels
("Korpus-Releases" / "Release Log") remain instance-specific.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Change-Id: Ie02bc64acdff5b6123ee1fd8898f514ba7ec7d35
2 files changed