Mirrors codemirror_bridge.rs: Reflect::get + unchecked_into for the
IIFE object literal window.XtermTerminal, XtermOptions as wasm-bindgen
extern type (TS class survives erasure), TerminalHandle with Drop →
destroy(). WASM-only (pub mod wasm gated on target_arch = wasm32).
Dioxus.toml: register /xterm/terminal.{css,js} in both prod and dev
resource arrays. CSS is emitted as a separate file by vite lib mode
(cssCodeSplit:false still extracts one CSS file for IIFE).
