fix: hide nonfatal pre-start send warnings

static/messages.js

@@ -216,6 +216,16 @@ function _clearStaleBusyStateBeforeSend({compressionRunning=false}={}){
   return true;
 }
 
+function _runOptionalPreStartUiStep(label, fn){
+  try{
+    return typeof fn==='function'?fn():undefined;
+  }catch(e){
+    const message=e&&e.message?e.message:String(e||'unknown error');
+    try{console.warn('[webui] optional pre-start UI step failed', label, message);}catch(_){ }
+    return undefined;
+  }
+}
+
 function _sessionTitleLooksDefaultOrProvisional(titleText, provisionalText){
   const title=String(titleText||'').replace(/\s+/g,' ').trim();
   if(!title||title==='Untitled'||title==='New Chat')return true;

tests/test_inflight_send_start_race.py

@@ -78,6 +78,10 @@ def test_pre_start_optimistic_ui_helpers_cannot_block_chat_start():
     assert "try" in helper_body and "catch" in helper_body, (
         "optional pre-start UI helper wrapper must catch errors before /api/chat/start"
     )
+    assert "setStatus(`UI warning before send:" not in helper_body, (
+        "non-fatal pre-start UI helper failures should stay in the console; visible status flashes "
+        "look like real send errors even though /api/chat/start continues"
+    )
     assert "_runOptionalPreStartUiStep" in pre_start, (
         "send() should wrap optimistic sidebar/title/polling helpers before /api/chat/start"
     )