"Use Option as Meta key" was read into `altIsMeta` but only applied to the
mouse alt-click options (`altClickMovesCursor`). xterm.js's `macOptionIsMeta`
— the option that actually makes Option emit ESC-prefixed (Meta) sequences —
was never set, so on macOS Option kept producing layout characters (ƒ, ∫, …)
and readline/zle word shortcuts (Alt+f, Alt+b, Alt+Backspace) were dead.
Extract the altAsMeta→xterm mapping into one tested helper used by both the
terminal init path (createXTermRuntime) and the live settings sync
(Terminal.tsx) so the two can't drift again.
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
陈大猫