fix: prevent agent debug from blocking chat

ai_knowledge_base_v2/apps/user-client/src/components/ChatComposer.vue

@@ -23,14 +23,23 @@ function resize() {
   element.style.overflowY = element.scrollHeight > 108 ? "auto" : "hidden";
 }
 
-function send() {
+async function send() {
   const text = input.value.trim();
   if (!text) return;
+  // Sending has been accepted by the composer. Clear immediately instead of
+  // keeping the submitted text visible until the entire AI stream finishes.
+  input.value = "";
+  await nextTick();
+  resize();
   emit("send", text, async (success) => {
-    if (!success) return;
-    input.value = "";
-    await nextTick();
-    resize();
+    // Restore only when the parent rejected/failed the request and the user has
+    // not entered replacement text in the meantime.
+    if (!success && !input.value) {
+      input.value = text;
+      await nextTick();
+      resize();
+      textarea.value?.focus();
+    }
   });
 }