- [ ] There's a unicode <?> being displayed in opencode [ON HOLD]
  - Investigated 2026-05-14: patterm passes ghostty grapheme codepoints
    through unchanged (vt/ghostty.go:452-462), so the `<?>` glyph is
    most likely the *host* terminal's font fallback for opencode's
    Nerd Font private-use codepoints, not a patterm substitution.
    Need a concrete reproduction (which codepoint, which host
    terminal/font) before changing rendering.