Fix Japanese IME exits on iPhone by checking e.isComposing

Skip the Gradio sync while an IME composition is active so that
iOS Safari does not kill the keyboard session mid-kanji input.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

static/gallery.js

@@ -185,7 +185,7 @@ function init() {
         if (e.dataTransfer.files.length) processFiles(e.dataTransfer.files);
     });
 
-    if (promptInput) promptInput.addEventListener('input', syncPromptToGradio);
+    if (promptInput) promptInput.addEventListener('input', (e) => { if (!e.isComposing) syncPromptToGradio(); });
 
     window.__setPrompt = function(text) {
         if (promptInput) { promptInput.value = text; syncPromptToGradio(); }