Expand description
Turns raw Markdown into a flat list of Block nodes — port of scanner.ts
/ Scanner.java. Offsets in stored spans are UTF-16 code units; the line
splitter keeps a running (byte, UTF-16) dual cursor and per-line regex offsets
are converted from bytes to UTF-16.
Following Scanner.java, scan takes no plugins parameter — there is no
scanner-plugin hook in this port.