feat: add OG image for website link sharing

fix: revert linesChanged to git diff only

chore: bump version to v1.21.0

Merge pull request #49 from uppinote20/feature/refactor-simplify-review

fix: remove redundant hasData flag in renderGeminiSection

chore: rebuild dist

fix: address PR review feedback

test: add tests for 9 previously untested source files

chore: add @tested/@covers bidirectional test map markers

chore: rebuild dist

fix: resolve 4 pre-existing test failures

chore: rebuild dist

refactor: consolidate check-usage render functions

perf: convert keychain and codex exec to async

chore: rebuild dist