feat: t4g support

src/lib/ccos/attachment.ts

@@ -0,0 +1,26 @@
+import type { Attachment } from "svelte/attachments";
+import { browser } from "$app/environment";
+import { persistentWritable } from "$lib/storage";
+
+export const emulatedCCOS = persistentWritable("emulatedCCOS", false);
+
+export function ccosKeyInterceptor() {
+  return ((element: Window) => {
+    const ccos = browser
+      ? import("./ccos").then((module) => module.fetchCCOS(".test"))
+      : Promise.resolve(undefined);
+
+    function onEvent(event: KeyboardEvent) {
+      ccos.then((it) => it?.handleKeyEvent(event));
+    }
+
+    element.addEventListener("keydown", onEvent, true);
+    element.addEventListener("keyup", onEvent, true);
+
+    return () => {
+      ccos.then((it) => it?.destroy());
+      element.removeEventListener("keydown", onEvent, true);
+      element.removeEventListener("keyup", onEvent, true);
+    };
+  }) satisfies Attachment<Window>;
+}