426e23d8be
Format and tidy enforce only on lines changed in PRs (diff-only via git-clang-format and clang-tidy-diff.py) — existing files keep their current style until edited. Mass reformat deferred; .git-blame-ignore-revs stub is in place for whenever that happens. Sanitizer lane builds with -fsanitize=address,undefined and runs the unit suite. continue-on-error: true initially so we can triage findings without blocking PRs. UB categories pervasive in the Hash9 C cascade (alignment, signed-integer-overflow, vptr) are suppressed pending file-by-file fixes. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>