Folds all changes since 0.7.10 into 0.7.12 (0.7.11 was unpublished from
npm): size-adaptive codegraph_explore output budget (#185/#187), line
numbers in explore source sections (#188), explore-first tool guidance
(#191), language-neutral source-omission markers, and Kotlin/Swift
test-file detection (#191).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>