Evaluate ghostty-web as xterm.js replacement for TUI web rendering

Context

We currently use @xterm/xterm (v6.0.0), @xterm/addon-fit, and @xterm/headless in @overeng/tui-react for Storybook terminal previews and testing.

ghostty-web is a WASM-compiled terminal emulator built from Ghostty's native engine with xterm.js API compatibility. It's designed as a drop-in replacement (import { Terminal } from 'ghostty-web' instead of @xterm/xterm).

Why consider this

• Uses Ghostty's battle-tested native terminal parser (compiled to WASM) rather than a JS reimplementation
• Better handling of complex scripts, unicode, and advanced terminal features (e.g. XTPUSHSGR/XTPOPSGR)
• Zero external dependencies
• API-compatible with xterm.js — should be a minimal migration

Scope

Affected code:

• packages/@overeng/tui-react/src/storybook/TuiStoryPreview.tsx (xterm.js Terminal + FitAddon)
• packages/@overeng/tui-react/src/storybook/theme.ts (xterm theme)
• packages/@overeng/tui-react/test/helpers/virtual-terminal.ts (@xterm/headless)

Open questions

• Does ghostty-web support all the xterm.js APIs we use (Terminal, FitAddon, headless mode)?
• Performance characteristics for our use case (Storybook timeline playback with frequent writes)?
• Maturity — currently at v0.4.0, actively maintained by Coder

Read the three affected files: TuiStoryPreview.tsx, theme.ts, and test/helpers/virtual-terminal.ts. Compare their Terminal, FitAddon, and headless usage with ghostty-web, then exercise Storybook timeline playback and virtual-terminal tests with frequent writes. Done means the API compatibility, performance, and maturity findings support a clear migration recommendation.