Upstream siwen's 太虛大師全書 post-process scripts as library-only
CommonMark-safe passes — ~14k paragraph merges and ~1.5k head
re-levels per 62-book empirical baseline.

Hardened across 15 rounds of Codex review for multi-paragraph list
items, indented code blocks (4-space + tab), empty ATX headings,
link reference definitions, CRLF / mixed line endings, fence
inside list, type 1-6 HTML block starters (case-insensitive, not
inline tags like <span>). Known HTML type 1-5 close-tag and
multi-line link-ref limitations documented in module docstring.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>