fix(keymap): Don't run the Enter that commits an input-method candidate

WebKit sends the Enter (or Space) that commits a candidate after compositionend,
with isComposing already false and keyCode 229. Handlers that checked isComposing
alone ran it: dialogs confirmed and shortcuts fired while typing Chinese or
Japanese. isImeKey() checks both, and every keydown handler that skipped
composition uses it.

src/platform/ime.ts

@@ -0,0 +1,8 @@
+/**
+ * True while an input method is composing, including the key that ends it: WebKit sends the
+ * Enter / Space that commits a candidate after `compositionend`, with `isComposing` already
+ * false and keyCode 229, so a handler checking `isComposing` alone runs that Enter.
+ */
+export function isImeKey(e: KeyboardEvent): boolean {
+  return e.isComposing || e.keyCode === 229;
+}

src/platform/keymap.ts

@@ -18,6 +18,7 @@ import { intellijWindows } from "./keymaps/intellij-windows";
 import { vscodeMacos } from "./keymaps/vscode-macos";
 import { vscodeWindows } from "./keymaps/vscode-windows";
 import { usePlatform } from "./platformInfo";
+import { isImeKey } from "./ime";
 
 export type Keymap = Record<string, string[]>;
 
@@ -439,7 +440,7 @@ export function installKeyboardDispatcher(target: Window = window, now: () => nu
     if (runHeldGesture(e)) return reset();
     resetTap();
     otherKeyAt = e.key === "Escape" || e.key === "Tab" ? -Infinity : now();
-    if (e.isComposing) return;
+    if (isImeKey(e)) return;
     const stroke = strokeOf(e);
     if (!stroke) return;
     const chord = pending.length > 0;