Bump version to 1.2.0 (Android versionCode 5) and write the 1.2.0 changelog.
Coverage settings exclude the fuzz harness, server probe and test assembly; CI fails if Core drops below 95% lines or 88% branches. The gitignore no longer swallows tests/coverage.runsettings.
Offline test suite on Ubuntu and Windows, a random-input fuzz smoke per parser target, and docs/check-docs.sh on every push to main and PR.