Closes the v0.9.0 release loop on top of Phase 9a-Newton + Phase 8b-Lite:
* CHANGELOG.md (NEW) — Keep-A-Changelog format, with v0.9.0 entry
detailing all Phase 9a / 9b / 8b-Lite contents and the doc-audit
corrections that landed via PR #10.
* CITATION.cff — version 0.7.0 → 0.9.0, date 2026-05-18 → 2026-05-22.
* Stale HDS-port stubs removed (13 GTEST_SKIPs total):
- code/tests/test_spherical_functional.cpp
- code/tests/test_hyper_ideal_functional.cpp
- code/tests/test_hyper_ideal_hyperelliptic_utility.cpp
These referenced a "HDS port (Phase 4)" that never happened —
CoHDS was intentionally replaced by CGAL::Surface_mesh, and the
functional tests live in code/tests/cgal/test_*_functional.cpp.
* Test-count updates everywhere:
- Non-CGAL 36 → 23 (drop = 13 deleted stubs)
- CGAL 176 → 227
- Total 212 → 250 (+38 net, 0 skipped)
Files: README.md, CLAUDE.md, CHANGELOG.md, scripts/try_it.sh,
doc/api/tests.md, doc/contributing.md, doc/getting-started.md,
doc/math/validation.md.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>