Multiple font fallback chain: configure fallbacks in config.toml with ordered list of fonts (CJK, emoji, Nerd Font)

Wide character support: CJK, fullwidth forms, and wide emoji render correctly across 2 terminal columns

Cell Width field (0=continuation, 1=normal, 2=wide) for precise wide character tracking

terminal.RuneWidth() — single source of truth for character width calculation

15 table-driven tests for wide char placement, erase, resize, and width detection

Erase operations (EraseInLine, EraseInDisplay, InsertChars, DeleteChars) handle wide char boundaries correctly

Selection copy skips continuation cells — no duplicate characters in clipboard

Mouse click and drag snap to parent cell when landing on wide char continuation

Word selection expands correctly across wide characters

Search highlights span the correct columns for wide characters (colMap pattern)

URL detection handles wide characters in surrounding text

Resize fixes truncated wide chars at boundaries and orphaned continuation cells