3073230f58
Second per-module ratchet under ADR 0004. Add a branch-coverage suite for the YAML-subset parser's reachable error/edge cases: literal `#`, blank-line skipping, unterminated/empty/bad inline list+dict, quoted commas in flow, missing `:` separators, non-bare keys, empty block -> None, bare-dash nested lists, quoted-colon list scalars, nested/empty list-item mappings, duplicate keys, document-level rejections (block scalars, anchors, tags, non-column-0, top-level list), and empty frontmatter. yaml_subset.py: 82% -> 95%. The remaining misses are dead/defensive guards (e.g. the unreachable bool branch, indent-mismatch raises that the callers never trigger). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NkwFXLFff9PYPy4wgVBJp9