- Identified ToUnicodeMap::add_mapping() as primary creation point
- Located at crates/pdftract-core/src/font/cmap.rs:86-88
- Uses HashMap<Vec<u8>, Vec<char>> for storage
- Called from parse_beginbfchar() and parse_beginbfrange()
- Documents call sites and data structure for skip logic implementation
Closes bf-o4nrq
