feat: replace keypress with isComposing

Ref: https://developer.mozilla.org/en-US/docs/Web/API/Element/keydown_event#keydown_events_with_ime

static/script.js

@@ -9,9 +9,7 @@ const session_uuid = self.crypto.randomUUID();
 
 sendButton.addEventListener("click", () => {
   sendMessage();
-}
-);
-
+});
 
 promptInput.addEventListener("input", () => {
   if (promptInput.value.split("\n").length == 1) {
@@ -22,7 +20,7 @@ promptInput.addEventListener("input", () => {
   }
 });
 
-promptInput.addEventListener("keypress", () => {
+promptInput.addEventListener("keydown", () => {
   handleKeyPress(event);
 });
 
@@ -107,6 +105,10 @@ function hideTypingIndicator() {
 }
 
 function handleKeyPress(event) {
+  if (event.isComposing || event.keyCode === 229) {
+    return;
+  }
+
   if (event.key == "Enter" && !event.shiftKey) {
       event.preventDefault();
       sendMessage();